由when, as soon as, before, after, as, until等引导的时间状语从句以及由if, unless, as long as, in case等引导的条件状语从句不能直接用将来时态，遇此情况英语习惯上用一般现在时代替一般将来时。如：

　　趁早动手，免得忘了。

　　误：Do it before you will forget.

　　正：Do it before you forget.

　　我到达那儿后就给你写信。

　　误：I’ll write to you after I will get there.

　　正：I’ll write to you after I get there.

　　如果他来，请告诉我一声。

　　误：In case he will come, let me know.

　　正：In case he comes, let me know.