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
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
答
选D主将从现
答
D
答
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.