第1个回答 2012-07-27
常见的有以下四种情况:
一、条件状语从句的主句是一般将来时,那么从句常常用一般现在时。
如: When I grow up, I’ll be a nurse and look after patients.
我长大后要当一名护士,照顾病人
二、如果主句是祈使句,那么从句通常要用一般现在时
如:Don’t laugh at me when I make a mistake.
我犯错误的时候不要笑话我。
三、如果主句是含有情态动词的一般现在时,根据需要从句多用一般现在时
如:You should be quiet when you are in the reading room
在阅览室时应保持安静
四、 如果if的条件状语从句遇到变换间接和直接时 , 祈使句应用not to....
如; She said not to close the window
常见的时间状语从句的连词有:as soon as,when,while ,as,until等
主将从现说的是在含有时间状语从句和条件状语从句的主从复合句中,如果主句的时态是一般将来时,那么从句要用一般现在时。例如:
I will tell him about it when he comes.
If it is fine tomorrow, we will go outing.
如果主句的时态是过去将来时,那么从句要用一般过去时。例如:
He said that he would have another try if he had the chance.
I knew he could help me if he was free the next day.
主要标志有:if\ unless \until\ when \as soon as本回答被网友采纳
第2个回答 2012-07-27
if 引导的条件状语从句 只有if 是如果的意思才适用主将从现例
i will go shpping if it doesn't rain tomorrow.如果明天不下雨我就去购物。
i don‘t know if Tom will come here this afternoon.我不知道 是否tom 今天下午会来。(这不适用主将从现)
as soon as i will call you as soon as he comes back.
unless i am waiting for my sister. i won't leave unless she arrives.
表示条件的是从句,比如第一句 明天天不下雨是条件,又叫条件状语从句所以从句是if it doesn't rain tomorrow。一般现在时;主句就是 i will go shpping 将来时
同理自己分析下面的句子 i will call you as soon as he comes back条件
i am waiting for my sister. i won't leave unless she arrives.条件