【病句诊断】

We will complete the road by the time you come back next year.

【辨析讲解】

句中有个时间状语，by the time you come back next year，这个是指到修好路这个动作到将来的某个时间（也就是明年你回来的那个时间）为止完成。如果要表示在将来某一时间之前已完成的动作，并往往对将来某一时间产生影响。这样就需要用将来完成时，而我们句子句中用的是一般将来时。这个句子是时态错误。

【诊断结果】

We will have completed the road by the time you come back next year.

【举一反三】

By the time you get home I will have cleaned the house from top to bottom. 你到家之前我将把房子彻底打扫一遍。

【考考你】

What will have completed by the end of this year?