1. He didn't know he __________ (own) the new computer already.
2. He offered __________ (help) us.
3. There are still some trees __________ (plant)
4. __________ (read) the instructions before you use the machine is necessary.
5. Don't you hear him __________ (sing) next door?
6. Have you seen a wallet __________ (lie) on the ground?
7. __________ (not know) his telephone number, I couldn't ring him up.
8. This is a book __________ (write) by Lu Xun.
9. Would you mind my__________ (open) the door?
10. My TV set needs __________ (mend).

A. has
B. have
C. is
D. are