单选题 5.Historian: Newton developed mathematical concepts and techniques that are fundamental to modern calculus. Leibniz developed closely analogous concepts and techniques. It has traditionally been thought that these discoveries were independent. Researchers have, however, recently discovered notes of Leibniz's that discuss one of Newton's books on mathematics. Several scholars have argued that since the book includes a presentation of Newton's calculus concepts and techniques, and since the notes were written before Leibniz's own development of calculus concepts and techniques, it is virtually certain that the traditional view is false. A more cautious conclusion than this is called for, however. Leibniz's notes are limited to early sections of Newton's book, sections that precede the ones in which Newton's calculus concepts and techniques are presented.
In the historian's reasoning, the two portions in boldface play which of the following roles?

A、 The first is a claim that the historian rejects; the second is a position that that claim has been used to support.
B、 The first is evidence that has been used to support a conclusion about which the historian expresses reservations; the second is that conclusion.
C、 The first provides evidence in support of a position that the historian defends; the second is that position.
D、 The first and the second each provide evidence in support of a position that the historian defends.
E、 The first has been used in support of a position that the historian rejects; the second is a conclusion that the historian draws from that position.

【正确答案】 B

【答案解析】Argument Construction
Situation A historian discusses a controversy about whether or not Leibniz developed calculus concepts and techniques independently of Newton.
Reasoning What argumentative roles do the two portions in boldface play in the passage? The first four sentences of the passage simply provide background information. Both boldface sections are within the fifth sentence, which reports an argument by several scholars. The key word since indicates that the first boldface section is a premise in the scholars' argument. A second premise preceded by another since follows in the next clause. The final clause of the fifth sentence reveals that the second boldface section is the conclusion of the scholars' argument. In the sixth sentence, the historian expresses misgivings about the scholars' conclusion, for reasons presented in the seventh and final sentence.
A The historian does not reject the claim that Newton's book includes a presentation of Newton's calculus concepts and techniques. Instead, the historian merely points out that Leibniz's notes do not cover those sections of Newton's book.
B Correct. The first boldface section is one of two premises in the scholars' argument, and the second boldface section is that argument's conclusion. In the following sentence the historian expresses reservations about that conclusion.
C The historian does not defend the scholars' conclusion but rather expresses misgivings about it.
D The second boldface section is the scholars' conclusion and does not present any evidence. Nor does it support the historian's position that a more cautious conclusion is called for.
E The second boldface section presents not the historian's conclusion but rather the scholars' conclusion, about which the historian expresses misgivings.
The correct answer is B.