Giải thích các bước giải:
1: Where does he work?
2: What was the matter with you? I have a cough.
3: What did you do yesterday? I rode a bike in the park.
4: Last week, I bought some souvenir gifts for my friend.
5: I visited my grandpa and grandma on Tet holiday.
6: What's the matter with him? He has a toothache.
7: She has a fever. She should go to bed.