Question

The man we followed suddenly stopped and looked as if          whether he was going in the right direction

1. A.
   seeing
2. B.
   having seen　
3. C.
   to see
4. D.
   to have seen

Answer 1

C
解析：
as if to see="as" if he were(was) to see，as if引导的表语从句或者方式状语从句可以采用这种省略形式。