Question

I looked at the young man, wondering ________ .

1. A.
   when had I seen him before
2. B.
   that where I had seen him before
3. C.
   if I saw him before
4. D.
   whether I had seen him before

Answer 1

D
注意这里的see应用过去完成时，wondering所带的现在分词短语作伴随状语，表示与谓语动词looked同时发生的动作，因此wondering后带的whether引导的宾语从句中see的动作应该在“过去的过去”，同时，从句应使用陈述语序。