24. To estimate the expansion rate of the universe is a notoriously difficult problem because there is a lack of a single yardstick that all distances can be measured by.

A、 To estimate the expansion rate of the universe is a notoriously difficult problem because there is a lack of a single yardstick that all distances can be measured by.
B、 Estimating the expansion rate of the universe is a notoriously difficult problem because there is no single yardstick by which all distances can be measured.
C、 Because there is a lack of a single yardstick to measure all distances by, estimating the expansion rate of the universe is a notoriously difficult problem.
D、 A notoriously difficult problem is to estimate the expansion rate of the universe because a single yardstick is lacking by which all distances can be measured.
E、 It is a notoriously difficult problem to estimate the expansion rate of the universe because by no single yardstick can all distances be measured.

【正确答案】 B

【答案解析】 Rhetorical Construction; Logical Predication
The sentence seeks to explain the difficulty of estimating the expansion rate of the universe and uses a because-clause to present the explanation. Issues in the given sentence include the following: is the infinitive verb form to estimate best here? And is there a more straightforward and more readable way to express the explanation?
A The wording with the infinitive verb form to estimate is less than ideal here (as opposed to how to estimate, for example). The phrase there is a lack of a single yardstick is wordy. The placement of the preposition by so far from the relative pronoun it governs (that) is unnecessarily awkward.
B Correct. Use of the verbal noun estimating is acceptable here. The phrase there is no single yardstick is much more direct and readable than there is a lack of a single yardstick. The preposition by is adjacent to which, the relative pronoun that it governs.
C The phrase there is a lack of a single yardstick is wordy. The placement of the preposition by at the end of the phrase a single yardstick to measure all distances by is unnecessarily awkward, in that it separates by from the noun that it is meant to govern.
D Compared with the given sentence, this sentence involves a reordering of the ideas and a shifting of emphases in a way that is confusing. For example, is this sentence to be understood as citing one instance of "a notoriously difficult problem"? This was not the purpose of the given sentence. In addition, the phrase to estimate is less clear than would be how to estimate. Finally, the wide separation of the because-clause from the reference to difficulty produces a sentence that is unnecessarily awkward, if not incoherent (for example, structurally it seems to make the adverbial because-clause modify the verb estimate). Contrast this with the given sentence, where the because-clause is placed adjacent to the phrase difficult problem.
E The phrase to estimate is less clear than would be how to estimate. The because-clause, which is meant to explain why estimating the expansion rate of the universe is difficult, is too widely separated from the reference to difficulty. In the because-clause, the inversion of the normal subject-verb order is unnecessarily awkward.
The correct answer is B.