A
1、was playing
2、Were … reading
3、was buying
4、was waiting
5、were talking
6、were having
7、were listening
B
2、I was walking to a computer shop.
3、I was buying some computer games in the computer shop.
4、I was having dinner at home.
5、I was playing computer games in my study.
C
1、 was lying in bed; was visiting the dentist
2、was doing some shopping; was playing
3、was having lunch; was drinking tea with Steve
4、was swimming; was seeing a film at the cinema
5、was choosing some videos; was collecting
6、was watching a football match on TV; was cooking