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。
1as soon as的用法
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.
