过去进行时如何分辨did与was/were doing

Question

1.过去进行时如何分辨did与was/were doing?
2.单选：I _______ when he arrived.
A was shopping B shopped C shopping D shops
3.单选I ____ while he was playing the piano.
A was shopping B shopped C shopping D shops

4.填空what ______ you ____ when he arrived?
5.填空what_______you_______while he was shopping?

Answer 1

1、过去式用did，过去进行时用was/were doing
2、A
3、A
4、were doing
5、were doing
这里需要注意when\while的区别。

Answer 2

1 did 是一般过去时 was /were doing 是过去进行时
2 A
3 A
4 were doing
5 were doing

Answer 3

1.过去进行时was/were doing；过去式did
2.A
3.A
4.were you
5.were you