Information and Ideas · Reading & Writing
Central Ideas and Details
The main idea of a passage, or a specific detail it states. Everything you need is on the page; nothing has to be inferred beyond it.
38 questions in the bank · 11 easier · 19 medium · 8 harder · this domain is ≈26% of the section
What to watch for
A main-idea answer must cover the whole passage, not one supporting example. A detail answer must be something the text actually says, not something it makes likely.
How the question is worded
These are the actual stems used in the bank — the SAT reuses a small set of wordings, and recognising them saves time on test day.
- Which choice best states the main idea of the text?
- According to the text, what role does glucose play in the wood frog's winter survival?
- According to the text, what happens when cracks in Roman harbor concrete reach the lime lumps within it?
- Which choice best describes the main idea of the text?
Worked examples
easyGreg McPherson spent his career at the Forest Service measuring street trees —…
Greg McPherson spent his career at the Forest Service measuring street trees — canopy area, leaf surface, the runoff that ran off anyway. For most of the twentieth century, city planners treated street trees as decoration — pleasant, but first against the budget wall in hard years. Recent work by urban foresters reframes them as infrastructure: a mature canopy measurably cools pavement, absorbs stormwater that would otherwise tax drains, and extends the life of the asphalt beneath it. On this accounting, a tree is less like a flowerbed than like a quiet, self-repairing utility.
Which choice best states the main idea of the text?
- A. City budgets through the twentieth century were frequently too small to maintain the parks properly in hard years
- B. Mature trees can measurably lower the temperature of the pavement lying beneath them
- C. Street trees are increasingly understood as functional urban infrastructure rather than mere ornament.
- D. Cities ought to replace their storm drains with plantings of large canopy trees
Answer: C. Street trees are increasingly understood as functional urban infrastructure rather than mere ornament.
Explanation
The passage's arc runs from the old view (decoration) to the new one (infrastructure), with cooling, stormwater, and asphalt as supporting evidence. The infrastructure-not-ornament choice captures that reframing. B is a single supporting detail, A inflates a background remark, and D proposes a replacement the text never suggests.
mediumThe following text is an original essay written for this exercise. Every trans…
The following text is an original essay written for this exercise. Every translator of poetry eventually meets a line that will not cross the border intact. The choice at that checkpoint defines a philosophy. Some smuggle the line's music through and let the literal sense pay the toll; others deliver the dictionary meaning and mourn the melody left behind. What no honest translator claims is to have carried everything: the craft is not in avoiding the loss but in choosing it wisely, and in writing a new line whose own beauty makes the reader forget to ask what was surrendered.
Which choice best states the main idea of the text?
- A. Skilled translation of poetry means choosing deliberately which qualities of a line to sacrifice
- B. Poetry, unlike prose, cannot be carried between languages in any way that means much, whatever the translator tries
- C. Translators ought always to preserve a poem's sound at the expense of its literal meaning, whatever else is lost
- D. Dictionaries are of only limited use to a translator working on a poem rather than on a piece of prose
Answer: A. Skilled translation of poetry means choosing deliberately which qualities of a line to sacrifice
Explanation
The essay's crux is "the craft is not in avoiding the loss but in choosing it wisely." A states exactly that. C elevates one of the two described camps into a rule the author never endorses; B overshoots into impossibility the passage denies (translators do the work); D literalizes a passing metaphor.
hardThe New Bedford Whaling Museum holds thousands of logbooks from the American w…
The New Bedford Whaling Museum holds thousands of logbooks from the American whaling fleet, kept in a hand that had nothing else to do for months at a time. It is often said that the great library of the nineteenth-century whaling ship was the ocean itself, but logbooks tell a bookish counter-story. Crews traded novels between vessels at sea with the formality of diplomats; a captain's inventory might list harpoons and Homer in adjacent lines; and the marginalia in surviving shipboard volumes — arguments, jokes, homesick verses — suggest reading was not an escape from the voyage so much as one of its social centers, an activity crews organized their scarce leisure around.
Which choice best states the main idea of the text?
- A. Captains of whaling vessels valued the literary works aboard more highly than they valued their equipment
- B. Sailors wrote a great deal more marginalia in the books they carried than readers on land did
- C. Nineteenth-century whaling crews had almost no leisure time at all during their longest voyages
- D. Logbooks and surviving books suggest that reading was a central, shared activity aboard whaling ships
Answer: D. Logbooks and surviving books suggest that reading was a central, shared activity aboard whaling ships
Explanation
The passage marshals three kinds of evidence (trades, inventories, marginalia) toward one claim: reading was a social center of shipboard life. C inverts a passing phrase ("scarce leisure" — some existed); A over-reads the Homer-next-to-harpoons detail; B invents a land comparison.