as soon as引导的时间状语从句是什么？

as soon as引导的时间状语从句的规则：若主句为一般将来时，从句常用一般现在时表将来；若主句不是一般将来时，那么从句的时态就要根据上下文来定。

举例：

1、指未发生的动作，规律是：主句一般将来时，从句用一般现在时代替一般将来时。

如：I will tell him the news as soon as he comes back.

注：有时，为了特意表达刚刚完成某事就如何如何，需要用现在完成时。

如：I will go with you as soon as I have washed my face.

2、指紧接着发生的两个短动作，主从句都用一般过去时。

如He took out his English books as soon as he sat down.

不过，我也见过从句和主句都用一般现在时的情况。

如：As soon as he finishes his classwork, he runs out of the class.他一做完课堂作业，就跑出了教室。

总之，记住那两种基本的情况，不把时态用得太混乱了就行了（比如后面从句里用了将来时，就绝对不允许了）。