Cars moved very slowly in the 1920s, but they ______
move more quickly than in 1910.
A. were to can B. did
C. will D. can
昨日习题答案：
The second book was _______by August 1952,
but two years late, the end was still nowhere in sight.
A. completed B. to have completed
C. to complete D. to have been completed
标准答案是：D.
本题分析：不定式的逻辑主语是the second book，所以用被动语态。