Central Ideas and Details practice questions

Central Ideas and Details questions

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1. 1Central ideas and detailsFoundation

   Biologist Amina Rahman recorded the number of native bee species in small urban gardens. Gardens with several kinds of flowering plants supported more bee species than gardens planted with only lawn grass. Which choice best states the central idea?Biologist Amina Rahman recorded the number of native bee species in small urban gardens. Gardens with several kinds of flowering plants supported more bee species than gardens planted with only lawn grass. Which choice best states the central idea?

   • ARahman studied only gardens outside cities.Rahman studied only gardens outside cities.
   • BPlant diversity in urban gardens can support greater bee diversity.Plant diversity in urban gardens can support greater bee diversity.
   • CUrban gardens cannot support native bees.Urban gardens cannot support native bees.
   • DLawn grass is the preferred food source for all bee species.Lawn grass is the preferred food source for all bee species.
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   Answer: Plant diversity in urban gardens can support greater bee diversity.Plant diversity in urban gardens can support greater bee diversity.

   The finding compares diverse flowering gardens with lawn-only gardens and reports more bee species in the diverse gardens. The other choices contradict or add claims not supported by the passage.The finding compares diverse flowering gardens with lawn-only gardens and reports more bee species in the diverse gardens. The other choices contradict or add claims not supported by the passage.

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2. 2Central ideas and detailsFoundation

   A city council replaced several parking spaces near a busy market with covered bicycle racks. Over the following year, vendors reported that weekday foot traffic rose while total sales stayed roughly the same. Which choice best states the central idea of the text?A city council replaced several parking spaces near a busy market with covered bicycle racks. Over the following year, vendors reported that weekday foot traffic rose while total sales stayed roughly the same. Which choice best states the central idea of the text?

   • AVendors organized to oppose the removal of the parking spaces.Vendors organized to oppose the removal of the parking spaces.
   • BThe change caused market sales to fall sharply.The change caused market sales to fall sharply.
   • CBicycle racks cost less to install than parking spaces do.Bicycle racks cost less to install than parking spaces do.
   • DThe change altered how people arrived at the market without changing overall sales.The change altered how people arrived at the market without changing overall sales.
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   Answer: The change altered how people arrived at the market without changing overall sales.The change altered how people arrived at the market without changing overall sales.

   The text reports one thing that changed (how people arrived, shown by foot traffic) and one that did not (total sales). The other choices add claims about opposition, cost, or falling sales that the text does not make.The text reports one thing that changed (how people arrived, shown by foot traffic) and one that did not (total sales). The other choices add claims about opposition, cost, or falling sales that the text does not make.

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3. 3Central ideas and detailsFoundation

   A cooperative bakery lets each member set the price of the bread they bake. Members report that prices have converged over time even though no rule requires it. Which choice best states the central idea?A cooperative bakery lets each member set the price of the bread they bake. Members report that prices have converged over time even though no rule requires it. Which choice best states the central idea?

   • ABread at the cooperative costs less than at other bakeries.Bread at the cooperative costs less than at other bakeries.
   • BMembers disagree about how bread should be priced.Members disagree about how bread should be priced.
   • CThe bakery introduced a pricing rule that members follow.The bakery introduced a pricing rule that members follow.
   • DPrices settled into a common range through the members' own choices rather than through a rule.Prices settled into a common range through the members' own choices rather than through a rule.
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   Answer: Prices settled into a common range through the members' own choices rather than through a rule.Prices settled into a common range through the members' own choices rather than through a rule.

   The text emphasizes convergence in the absence of a requirement. The other choices contradict the stated absence of a rule or add comparisons and disputes the text does not mention.The text emphasizes convergence in the absence of a requirement. The other choices contradict the stated absence of a rule or add comparisons and disputes the text does not mention.

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4. 4Central ideas and detailsStandard

   In a profile of a ceramic artist, the writer notes that the artist tests dozens of glaze mixtures before choosing one for a collection. This detail mainly emphasizes the artist'sIn a profile of a ceramic artist, the writer notes that the artist tests dozens of glaze mixtures before choosing one for a collection. This detail mainly emphasizes the artist's

   • Acareful experimental process.careful experimental process.
   • Breliance on accidental results.reliance on accidental results.
   • Cinterest in collecting antiques.interest in collecting antiques.
   • Dpreference for working alone.preference for working alone.
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   Answer: careful experimental process.careful experimental process.

   Testing many mixtures before selecting one demonstrates systematic experimentation. Nothing in the detail establishes the other characterizations.Testing many mixtures before selecting one demonstrates systematic experimentation. Nothing in the detail establishes the other characterizations.

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5. 5Central ideas and detailsStandard

   In an essay about the restoration of an old pipe organ, the writer spends most of the piece describing how the restorers photographed, numbered, and measured each pipe before removing it, and devotes a single closing sentence to the instrument's first concert. What does this proportion most suggest about the writer's focus?In an essay about the restoration of an old pipe organ, the writer spends most of the piece describing how the restorers photographed, numbered, and measured each pipe before removing it, and devotes a single closing sentence to the instrument's first concert. What does this proportion most suggest about the writer's focus?

   • AThe writer considers the organ less important than the building around it.The writer considers the organ less important than the building around it.
   • BThe writer believes the first concert was poorly attended.The writer believes the first concert was poorly attended.
   • CThe writer is more interested in the method of the restoration than in its result.The writer is more interested in the method of the restoration than in its result.
   • DThe writer thinks the restoration should not have been attempted.The writer thinks the restoration should not have been attempted.
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   Answer: The writer is more interested in the method of the restoration than in its result.The writer is more interested in the method of the restoration than in its result.

   Space is the evidence here: the process receives most of the essay and the outcome one sentence. The other choices introduce judgments the text does not make.Space is the evidence here: the process receives most of the essay and the outcome one sentence. The other choices introduce judgments the text does not make.

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6. 6Central ideas and detailsStandard

   A regional airline replaced its printed timetables with a mobile application. Bookings made more than a month in advance rose, while total bookings were unchanged and calls to the booking line fell by half. Which choice best states the central idea?A regional airline replaced its printed timetables with a mobile application. Bookings made more than a month in advance rose, while total bookings were unchanged and calls to the booking line fell by half. Which choice best states the central idea?

   • AMobile applications are cheaper for airlines than printed timetables.Mobile applications are cheaper for airlines than printed timetables.
   • BThe change shifted when and how passengers booked without changing how many did.The change shifted when and how passengers booked without changing how many did.
   • CPassengers booked more flights once the application launched.Passengers booked more flights once the application launched.
   • DThe airline lost passengers who preferred printed timetables.The airline lost passengers who preferred printed timetables.
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   Answer: The change shifted when and how passengers booked without changing how many did.The change shifted when and how passengers booked without changing how many did.

   Two things moved — timing and channel — and one did not: the total. The other options assert losses, costs, or growth the text explicitly rules out or never mentions.Two things moved — timing and channel — and one did not: the total. The other options assert losses, costs, or growth the text explicitly rules out or never mentions.

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7. 7Central ideas and detailsStandard

   A publisher offered two editions of a reference book: a printed volume and a subscription to the same text online. Libraries bought the printed volume at four times the rate of the subscription, and librarians surveyed said the printed volume was easier to lend to several readers in one day. Which choice best states the central idea?A publisher offered two editions of a reference book: a printed volume and a subscription to the same text online. Libraries bought the printed volume at four times the rate of the subscription, and librarians surveyed said the printed volume was easier to lend to several readers in one day. Which choice best states the central idea?

   • ALibrarians dislike reading text on screens.Librarians dislike reading text on screens.
   • BThe online subscription was more expensive than the printed volume.The online subscription was more expensive than the printed volume.
   • CA practical difference in how the two formats circulate, rather than a preference for print, explains the buying pattern.A practical difference in how the two formats circulate, rather than a preference for print, explains the buying pattern.
   • DPrinted reference books contain more information than online editions.Printed reference books contain more information than online editions.
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   Answer: A practical difference in how the two formats circulate, rather than a preference for print, explains the buying pattern.A practical difference in how the two formats circulate, rather than a preference for print, explains the buying pattern.

   The text pairs the buying pattern with a stated reason about lending, which is a practical constraint rather than a taste. Price, screen preference, and content are never mentioned.The text pairs the buying pattern with a stated reason about lending, which is a practical constraint rather than a taste. Price, screen preference, and content are never mentioned.

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8. 8Central ideas and detailsStandard

   A hospital replaced its paper wayfinding signs with digital screens showing the same information. Staff reported being asked for directions just as often as before, though visitors said the screens looked clearer. Which choice best states the central idea?A hospital replaced its paper wayfinding signs with digital screens showing the same information. Staff reported being asked for directions just as often as before, though visitors said the screens looked clearer. Which choice best states the central idea?

   • AVisitors ignored the new screens entirely.Visitors ignored the new screens entirely.
   • BA change that improved how the information looked did not change how well people found their way.A change that improved how the information looked did not change how well people found their way.
   • CHospital staff prefer answering questions in person.Hospital staff prefer answering questions in person.
   • DThe digital screens were harder to read than the paper signs.The digital screens were harder to read than the paper signs.
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   Answer: A change that improved how the information looked did not change how well people found their way.A change that improved how the information looked did not change how well people found their way.

   Two findings are reported: clarity improved and requests for directions did not fall. The other choices contradict the stated clarity or add attitudes the text never mentions.Two findings are reported: clarity improved and requests for directions did not fall. The other choices contradict the stated clarity or add attitudes the text never mentions.

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9. 9Central ideas and detailsStandard

   A city introduced a deposit on drink containers. Litter surveys found far fewer containers on the streets, while the total weight of street litter was almost unchanged. Which choice best states the central idea?A city introduced a deposit on drink containers. Litter surveys found far fewer containers on the streets, while the total weight of street litter was almost unchanged. Which choice best states the central idea?

   • AThe scheme changed what the litter consisted of rather than how much of it there was.The scheme changed what the litter consisted of rather than how much of it there was.
   • BThe deposit scheme failed to reduce litter of any kind.The deposit scheme failed to reduce litter of any kind.
   • CResidents began littering more of other materials in protest.Residents began littering more of other materials in protest.
   • DDrink containers make up most of a city's street litter.Drink containers make up most of a city's street litter.
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   Answer: The scheme changed what the litter consisted of rather than how much of it there was.The scheme changed what the litter consisted of rather than how much of it there was.

   One measure moved and the other did not, which is a change in composition. The scheme did reduce container litter, so it did not fail entirely, and nothing in the text suggests protest or gives containers' share of the total.One measure moved and the other did not, which is a change in composition. The scheme did reduce container litter, so it did not fail entirely, and nothing in the text suggests protest or gives containers' share of the total.

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10. 10Central ideas and detailsStandard

    Lichens are not single organisms but partnerships: a fungus supplies structure and holds moisture, while an alga or a cyanobacterium makes food by photosynthesis. Because neither partner can hold bare rock on its own, the pairing is often the first life to reach a new lava flow, and its slow chemical action begins to break the surface into soil.Which choice best states the main idea of the text?Lichens are not single organisms but partnerships: a fungus supplies structure and holds moisture, while an alga or a cyanobacterium makes food by photosynthesis. Because neither partner can hold bare rock on its own, the pairing is often the first life to reach a new lava flow, and its slow chemical action begins to break the surface into soil. Which choice best states the main idea of the text?

    • AA partnership lets lichens live where neither partner could survive alone, which is why they colonise bare rock first.A partnership lets lichens live where neither partner could survive alone, which is why they colonise bare rock first.
    • BThe fungus contributes more to a lichen than the alga does.The fungus contributes more to a lichen than the alga does.
    • CLava flows are the only surfaces on which lichens are found.Lava flows are the only surfaces on which lichens are found.
    • DSoil forms faster on lava than on other kinds of rock.Soil forms faster on lava than on other kinds of rock.
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    Answer: A partnership lets lichens live where neither partner could survive alone, which is why they colonise bare rock first.A partnership lets lichens live where neither partner could survive alone, which is why they colonise bare rock first.

    The text is built around one point: the partnership does what neither partner can. The comparison between the partners is never made, the lava flow is an example rather than the only case, and nothing is said about the speed of soil formation elsewhere.The text is built around one point: the partnership does what neither partner can. The comparison between the partners is never made, the lava flow is an example rather than the only case, and nothing is said about the speed of soil formation elsewhere.

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11. 11Central ideas and detailsStandard

    The Antikythera mechanism, recovered from a shipwreck in 1901, was cataloged for decades as a corroded lump of bronze. Imaging in the 1970s revealed at least thirty interlocking gears inside, arranged to model the motions of the sun and the moon. Nothing of comparable complexity survives from the next thousand years, which tells us less about what was built than about what happened to survive.Which choice best states the main idea of the text?The Antikythera mechanism, recovered from a shipwreck in 1901, was cataloged for decades as a corroded lump of bronze. Imaging in the 1970s revealed at least thirty interlocking gears inside, arranged to model the motions of the sun and the moon. Nothing of comparable complexity survives from the next thousand years, which tells us less about what was built than about what happened to survive. Which choice best states the main idea of the text?

    • AThe mechanism shows that ancient astronomy was more accurate than modern astronomy.The mechanism shows that ancient astronomy was more accurate than modern astronomy.
    • BImaging is the most valuable tool available to archaeology.Imaging is the most valuable tool available to archaeology.
    • COne surviving object can reveal a level of skill that the gap after it does not disprove.One surviving object can reveal a level of skill that the gap after it does not disprove.
    • DThe mechanism was the only geared device made in the ancient world.The mechanism was the only geared device made in the ancient world.
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    Answer: One surviving object can reveal a level of skill that the gap after it does not disprove.One surviving object can reveal a level of skill that the gap after it does not disprove.

    The last sentence is the argument: the thousand-year silence is evidence about survival, not about capability. The text never compares ancient and modern astronomy, and it says nothing was found of comparable complexity, which is not the same as saying nothing was made.The last sentence is the argument: the thousand-year silence is evidence about survival, not about capability. The text never compares ancient and modern astronomy, and it says nothing was found of comparable complexity, which is not the same as saying nothing was made.

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12. 12Central ideas and detailsStandard

    For most of the twentieth century the accepted account of how birds navigate was magnetic: they were thought to read the earth's field. That explanation survives, but it has been joined by others. Birds also use the position of the setting sun, the pattern of polarised light at dusk, remembered landmarks and, in some species, smell. What looked like one mechanism is now understood as several running at once, which is why removing any single one rarely stops a bird arriving.Which choice best states the main idea of the text?For most of the twentieth century the accepted account of how birds navigate was magnetic: they were thought to read the earth's field. That explanation survives, but it has been joined by others. Birds also use the position of the setting sun, the pattern of polarised light at dusk, remembered landmarks and, in some species, smell. What looked like one mechanism is now understood as several running at once, which is why removing any single one rarely stops a bird arriving. Which choice best states the main idea of the text?

    • ANavigation in birds relies on several mechanisms working together rather than one.Navigation in birds relies on several mechanisms working together rather than one.
    • BThe magnetic account of bird navigation has been disproved.The magnetic account of bird navigation has been disproved.
    • CSmell is the most important of a bird's navigational senses.Smell is the most important of a bird's navigational senses.
    • DBirds cannot navigate when the earth's magnetic field is disturbed.Birds cannot navigate when the earth's magnetic field is disturbed.
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    Answer: Navigation in birds relies on several mechanisms working together rather than one.Navigation in birds relies on several mechanisms working together rather than one.

    The last sentence states it directly, and the resilience it describes is the evidence. The magnetic account is said to survive rather than to have failed, no sense is ranked above the others, and redundancy is the opposite of the last claim.The last sentence states it directly, and the resilience it describes is the evidence. The magnetic account is said to survive rather than to have failed, no sense is ranked above the others, and redundancy is the opposite of the last claim.

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13. 13Central ideas and detailsStandard

    Coral reefs occupy less than a quarter of one percent of the ocean floor and support roughly a quarter of all marine species. That concentration is why bleaching events are reported as catastrophes rather than as losses proportionate to the area affected: the area is not what is being lost.Which choice best states the main idea of the text?Coral reefs occupy less than a quarter of one percent of the ocean floor and support roughly a quarter of all marine species. That concentration is why bleaching events are reported as catastrophes rather than as losses proportionate to the area affected: the area is not what is being lost. Which choice best states the main idea of the text?

    • AA reef's importance is out of all proportion to the space it occupies.A reef's importance is out of all proportion to the space it occupies.
    • BCoral bleaching now affects a quarter of the ocean floor.Coral bleaching now affects a quarter of the ocean floor.
    • CMarine species are declining faster than species on land.Marine species are declining faster than species on land.
    • DReefs cover less than one percent of the ocean floor.Reefs cover less than one percent of the ocean floor.
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    Answer: A reef's importance is out of all proportion to the space it occupies.A reef's importance is out of all proportion to the space it occupies.

    The text sets a tiny area against a quarter of all species and says the area is not the thing at stake. The last choice is one of the two facts rather than the point they are put together to make.The text sets a tiny area against a quarter of all species and says the area is not the thing at stake. The last choice is one of the two facts rather than the point they are put together to make.

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14. 14Central ideas and detailsStandard

    The word "quarantine" comes from the forty days Venetian officials required arriving ships to wait during outbreaks of plague. Forty was not a medical figure. It was drawn from religious tradition, and it happened to exceed the incubation period of the disease, which nobody at the time could have known. The measure worked, and the reasoning behind it was wrong.Which choice best states the main idea of the text?The word "quarantine" comes from the forty days Venetian officials required arriving ships to wait during outbreaks of plague. Forty was not a medical figure. It was drawn from religious tradition, and it happened to exceed the incubation period of the disease, which nobody at the time could have known. The measure worked, and the reasoning behind it was wrong. Which choice best states the main idea of the text?

    • AVenetian officials had a sophisticated understanding of incubation periods.Venetian officials had a sophisticated understanding of incubation periods.
    • BA measure can be effective for reasons its designers did not understand.A measure can be effective for reasons its designers did not understand.
    • CReligious tradition is a reliable guide to public health policy.Religious tradition is a reliable guide to public health policy.
    • DQuarantine periods should always last forty days.Quarantine periods should always last forty days.
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    Answer: A measure can be effective for reasons its designers did not understand.A measure can be effective for reasons its designers did not understand.

    The last sentence states it: the measure worked and the reasoning was wrong. The text says explicitly that nobody could have known about incubation, which rules out the claim that officials understood incubation, and it draws no recommendation from the coincidence.The last sentence states it: the measure worked and the reasoning was wrong. The text says explicitly that nobody could have known about incubation, which rules out the claim that officials understood incubation, and it draws no recommendation from the coincidence.

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15. 15Central ideas and detailsStandard

    A cuckoo lays in another bird's nest, and the chick that hatches ejects the host's own eggs. The behavior looks like a straightforward theft, and the arms race it produces is anything but: hosts have evolved eggs with signatures difficult to forge, cuckoos have evolved forgeries, and in some populations the hosts have begun rejecting their own eggs by mistake. Each side's improvement makes the other's task harder and its own errors costlier.Which choice best states the main idea of the text?A cuckoo lays in another bird's nest, and the chick that hatches ejects the host's own eggs. The behavior looks like a straightforward theft, and the arms race it produces is anything but: hosts have evolved eggs with signatures difficult to forge, cuckoos have evolved forgeries, and in some populations the hosts have begun rejecting their own eggs by mistake. Each side's improvement makes the other's task harder and its own errors costlier. Which choice best states the main idea of the text?

    • ACuckoos have entirely defeated the defenses of their hosts.Cuckoos have entirely defeated the defenses of their hosts.
    • BThe contest between cuckoos and hosts imposes rising costs on both sides.The contest between cuckoos and hosts imposes rising costs on both sides.
    • CHost birds cannot tell their own eggs from a cuckoo's.Host birds cannot tell their own eggs from a cuckoo's.
    • DCuckoo chicks are larger than the chicks they displace.Cuckoo chicks are larger than the chicks they displace.
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    Answer: The contest between cuckoos and hosts imposes rising costs on both sides.The contest between cuckoos and hosts imposes rising costs on both sides.

    The last sentence states it: each improvement raises the other side's difficulty and the cost of its own mistakes. Hosts rejecting their own eggs is offered as evidence of that cost, not as an inability to tell them apart.The last sentence states it: each improvement raises the other side's difficulty and the cost of its own mistakes. Hosts rejecting their own eggs is offered as evidence of that cost, not as an inability to tell them apart.

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16. 16Central ideas and detailsStandard

    The Antonine Wall was garrisoned for about twenty years and then abandoned; Hadrian's Wall, eighty miles south, was held for three centuries. The usual explanation is that the northern line was overextended. The archaeology complicates that: the Antonine forts were larger, better supplied and closer together. Whatever ended the occupation, it does not look like a garrison that could not hold its ground.Which choice best states the main idea of the text?The Antonine Wall was garrisoned for about twenty years and then abandoned; Hadrian's Wall, eighty miles south, was held for three centuries. The usual explanation is that the northern line was overextended. The archaeology complicates that: the Antonine forts were larger, better supplied and closer together. Whatever ended the occupation, it does not look like a garrison that could not hold its ground. Which choice best states the main idea of the text?

    • AThe Antonine Wall was abandoned because it was overextended.The Antonine Wall was abandoned because it was overextended.
    • BThe physical evidence does not support the usual explanation for the abandonment.The physical evidence does not support the usual explanation for the abandonment.
    • CHadrian's Wall was better built than the Antonine Wall.Hadrian's Wall was better built than the Antonine Wall.
    • DThe Antonine forts were too large to supply.The Antonine forts were too large to supply.
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    Answer: The physical evidence does not support the usual explanation for the abandonment.The physical evidence does not support the usual explanation for the abandonment.

    The text sets the standard explanation against three findings that cut against it and then declines to replace it. Saying an explanation does not fit is not the same as saying what did happen, and the passage is careful not to.The text sets the standard explanation against three findings that cut against it and then declines to replace it. Saying an explanation does not fit is not the same as saying what did happen, and the passage is careful not to.

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17. 17Central ideas and detailsChallenge

    The rebuilding of the bridge in 1902 is usually dated from the council minutes, which record the decision in March of that year. The masons' account book, though, shows stone being cut the previous November, and a bill for scaffolding was settled in January. The minutes record when the decision became official, not when the work began — a distinction that matters wherever committees are the only surviving source.Which choice best states the main idea of the text?The rebuilding of the bridge in 1902 is usually dated from the council minutes, which record the decision in March of that year. The masons' account book, though, shows stone being cut the previous November, and a bill for scaffolding was settled in January. The minutes record when the decision became official, not when the work began — a distinction that matters wherever committees are the only surviving source. Which choice best states the main idea of the text?

    • AA record of a decision can postdate the work it authorises, so minutes can mislead about timing.A record of a decision can postdate the work it authorises, so minutes can mislead about timing.
    • BThe council minutes for 1902 were falsified.The council minutes for 1902 were falsified.
    • CThe bridge was not rebuilt in 1902 at all.The bridge was not rebuilt in 1902 at all.
    • DAccount books are more reliable than minutes in every respect.Account books are more reliable than minutes in every respect.
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    Answer: A record of a decision can postdate the work it authorises, so minutes can mislead about timing.A record of a decision can postdate the work it authorises, so minutes can mislead about timing.

    The final sentence generalises the point: the minutes are accurate about what they record and misleading about what they are used for. Nothing suggests falsification, and the rebuilding is not in doubt — only its start date.The final sentence generalises the point: the minutes are accurate about what they record and misleading about what they are used for. Nothing suggests falsification, and the rebuilding is not in doubt — only its start date.

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