1,we heard the news during the lunch time
when we were having lunch, we heard the news
2,he was the first to come.I arrived there after him
when I arrived, he had been there
3,they often met each other for parties when they were in the same company
they used to meet each other for parties when they were in the same company
4,john has learned computer for two weeks
john started learning computer 2 weeks ago
5,my boss left the paty .He didn't say a word
my boss left the party without saying a word
6,mai left before my arrival
when I arrived , mai had left
7,she drove home .She listened to hẻ cả radio
while she was driving home, she was listening to her car radio
8,mary made a sandwich and then sat on the sofa to watch TV
after mary had made a sandwich, she sat on the sofa to watch tv
9,i and dave trided to ring each other at the same time
while ringing to each other , dave and i tried to do at the same time
10,mary wrote four books beftor she was twenty
by the time mary was twenty, she had written 4 books