He sets us so difficult a problem_________ I couldn’t work out.
| A．that | B．as | C．which | D．why |
. The flowers his friend gave him will die unless __________ every day.
A. watered B. watering
B. water D. to water
. Please remain __________ until the plane has come to a complete stop.
| A．to seat | B．to be seated |
| C．seating | D．seated |
. “Things __________ never come again!” I couldn’t help talking to myself.
| A．lost | B．losing |
| C．to lost | D．have lost |
. Jenny hopes that Mr. Smith will suggest a good way to have her written English __________ in a short period.
| A．improved | B．improving |
| C．to improve | D．improve |
. — Did Peter fix the computer himself?
— He __________, because he doesn’t know much about computers.
| A．has it fixed | B．had fixed it |
| C．had it fixed | D．fixed it |