1 最常见的是时间状语,也是我们最先学习的,i was cooking when you called me. 2. 引导定于从句, i never forgot the day when we first met. 3. 引导宾语从句,i didn't know when he got there. 4. 引导主语从句,when he came here is a se...
如果是时间状语从句,则基本有4种 1.表示有规律的,都用一般现在时 如:Water turns into steam when we heat it. 2.表示将来的事情,用主将从现(主句将来时,从句一般现在时) 如:I will tell him when he comes back. 3.表示过去两个有先后的动作,都用过去式 如:When he ...