1.I watching TV when he came in.2.My mother is cooking when

I 【加上was】watching TV when he came in.
My mother 【is改成was】 cooking when I got home.
I 【read改成 was reading】 a story book this time last night
What 【did改成were】 you 【 do 改成doing】at 5:00 p.m.yesterday?
He was 【talked改成talking】 to his mum at that time
这些都是考察过去进行时态的.was/were + doing 的形式

I(加上was) watching TV when he came in.
2.My mother is(is-- was) cooking when I got home.
3.I read(read- was reading) a story book this time last night.
4.What did(did- were) you do(do-- doing) at 5:00 p.m. yesterday?
5.He was talked (talked- talking)to his mum at that time