A
进行时+ when + 非进行时 I was wathcing TV when my mother came back.
进行时+ while + 进行时 I was wathcing TV when my mother was cooking.
记住这个区别就可以了
A
进行时+ when + 非进行时 I was wathcing TV when my mother came back.
进行时+ while + 进行时 I was wathcing TV when my mother was cooking.
记住这个区别就可以了