3. What a pity, Lan isn't good at English.
-> I wish
4. Nam last wrote to me five weeks ago.
-> Nam hasn't
5. He started to work for this bank five years ago.
->He has
6. If she doesn't save electricity, you will have to pay more.
-> Unless
7. "Why don't we plant vegetables in our school?" Trung said.
=> Trung suggested
8. He was very tired, but he went to work yesterday.
=> Even though
9. It is cold, so we can't go swimming.
=> If
13. I am busy so I can't go to the meeting.
=> If
14. You drink too much coffee that's why you can't sleep.
=> If