问题描述：
如何区别if 和when引导的状语从句
if i have time,i will help you.是不是也可以说成when i have time,i will help you.好像很多if 和when 都可以互相替换..但答却只能是其中的一个..它们的区别是怎么样?如when my mother is out,i have to take care of my sisters.and if my mother is out,have to take care of my sisters.
if i have time,i will help you.是不是也可以说成when i have time,i will help you.好像很多if 和when 都可以互相替换..但答却只能是其中的一个..它们的区别是怎么样?如when my mother is out,i have to take care of my sisters.and if my mother is out,have to take care of my sisters.
问题解答：
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