1, C
2, C
3. A
4. D
5. A
6. D
II.
7. Thanh is always complaining about the heaviness of my suitcase.
8. Mount Rushmore can be seen from 100 kilometers away.
III.
9. Mary is always leaving her dirty sockets on the floor.
10. The doorbell suddenly rang when I was watching TV at 8 o'clock yesterday.