Question

Nobody told us _____

1. A.
   what to do it
2. B.
   how to do
3. C.
   where to do
4. D.
   when to do it

Answer 1

D
考查疑问词+不定式的用法。What作do的宾语，it多余，排除A；B、C两项缺少宾语；D项不缺宾语。句意“没有人告诉我们什么时候做这件事。”故选D。