Question

Chang’e­2 did many experiments, ______ I think are of much help for knowing space

1. A.
   which
2. B.
   what
3. C.
   when
4. D.
   where

Answer 1

A
试题分析：考查定语从句。“嫦娥二号”做了许多试验，我认为这些试验对人们了解太空很有帮助。I think是插入语，可忽略，定语从句缺少主语，排除C、D；what不引导定语从句。故选A。
考点：考查定语从句