Chia độg từ ở thì qua khu tiep diễn hoac qua khu thích hợp
1.James saw/was seeing the accident when she was catching the bus.
2.what were you doing/ did you do when i called ?
3.i didn't visit /weren't visting him last summer holiday 
4.it rained/ was raining heavily last Match
5.While people were talking to each other , she reach/ was reading her book
6. My brother was eating/aet hamburgers every weekend last month.
7.While we were running /ran in the park ,Mary fell over 
8.Did you fiad/ were you finding your keys yesterday?
​9Who was she dancing / did she dance with at the party last night?
10. They were watching / watched  football  on TV at 10p.m .yesterday