1. My mother was cutting grass when I got there.
2. Lan has just finished her exercises.
3. A group of tourists is visiting that old town.
4. They found the mobile phone in his pocket.
5. Some naughty boys are laughing at that girl.
6. Are they building a new school for the poor?
7. Did you cook this fish for the dinner?
8. Mai and Bao didn't use much of it effectively.
9. The teacher doen't allow the students to leave the classroom.
10. I haven't seen him since last week.
