题目:
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.
选项:
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.
答案:
B