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题目： S and T are two-digit positive integers that have the same digits but in reverse order. If the positive difference between S and T is less than 40, what is the greatest possible value of S minus T?

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题目： How many of the integers between 40 and 100, inclusive, are even?

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题目： Line segments AB and CD are of equal length and perpendicular bisectors of one another. If a line segment is drawn connecting point A to point C, what is the measure of angle ACD?

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题目： If |a| = |b|, which of the following must be true? I. a = b II. |a| = -b III. -a = -b

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题目： Which of the following would result in a remainder of 7 when divided by 12? I. 151 II. 3,443 III. 5,995

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题目： Jane and Bob are currently x and 13 years old, respectively, where x is an integer. If Jane is older than Bob, what is the minimum value of x such that the sum of Jane's and Bob's ages has a units digit that is greater than the units digit of Bob's age?

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题目： A student committee that must consist of 5 members is to be formed from a pool of 8 candidates. How many different committees are possible?

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It can be inferred from the passage that the females of all phocid species differ from the females of all otariid species in that the female phocids

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题目：

The primary purpose of the passage is to

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According to the passage, until recently zoologists believed which of the following about all phocid mothers?

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The author of the passage mentions ringed seals most probably in order to

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According to some botanists, invasive plants are the second most serious threat, after habitat loss, to native species of plants and animals and to the maintenance of biologically diverse ecosystems.

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题目： During the eighteenth century, widespread changes in agriculture, known as the agrarian revolution, involving the large-scale introduction of enclosed fields, of new farming techniques and crops, and the substitution of commercial for subsistence farming.

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The relative prosperity of the first years of the twentieth century came to a halt in 1907 when drains on the money supply, revealing a weak national financial infrastructure of banking and credit, it precipitated an economic crisis that lasted nearly a year.

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The most vexing problem faced by researchers exploring wind-powered generation of electricity is achieving a constant flow of power from an unpredictable natural source that meets demand, but so the flow does not overload electrical grids with sudden voltage increases.