Question

When Madam Cuirie did the science experiement again, she was more careful where she _____ a mistake.

1. A.
   made
2. B.
   has made
3. C.
   was making
4. D.
   had made

Answer 1

D
由句意知“犯错误”是发生在“was more careful”之前，故用过去完成时。
【标签】动词时态