as soon as引导条件状语从句
例句
1、
As soon as relations improve they will be allowed to go
一旦关系有所改善，他们就可以获准离开。
2、
As soon as the necessity for action is over the troops must be withdrawn
一旦军事行动的必要性不复存在，军队就必须撤出。
例句： He’ll send us a message as soon as he arrives in Sichuan.
他一到四川就给我们发信息
as soon as表示“一…就”引导的是时间状语从句，其用法是主句用将来时，从句用一般现在时，故用arrives。
例句：
He will give a hands soon as someone asks for help．一有人求助，他就会伸出援手
用as soon as引导的条件状语从句，遵循主将从现的规则，从句主语someone，谓语动词用单数，ask for help求助，故答案是as soon as someone asks for．
as soon as 的用法一般是两种情况：
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．
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
这样的例句如下：I will give my daughter an apple to eat as soon as she comes back from school .
