Nobody told us A. what to do it B. how to do C. where to do D. when to do it

问题补充：

Nobody told us

A. what to do it

B. how to do

C. where to do

D. when to do it

答案：

A. what to do it

B. how to do

C. where to do

(答案→)D. when to do it

解析：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。