I don't know when Jim _____.I'll meet him at the airport when he ____.

问题描述:

I don't know when Jim _____.I'll meet him at the airport when he ____.
A.will return;return B.returns;will return C.returned;returned D.will return;returns 说明原因喔

D
第一个when 引导宾语从句,根据句意用一般将来时.
第二个when 引导时间状语从句,主句用将来时,从句用一般现在时.
意思是:我不知道吉姆将会什么时候回来.当他回来的时候我会在机场接他.