There are still many problemsbefore we are ready for a long stay on the Moon.
| A． | solving | B． | solved |
| C． | being solved | D． | to be solved |
---I suppos he’s late again. ----You ___ it.
| A．are guessing | B．will guess | C．guess | D．have guessed |
--Why didn’t Tom have his lunch? It’s already one o’clock.
---His pet bird ____this morning. He____still for quite a long time in his room crying.
| A．died; had sat | B．has died; has sat |
C．has died; is sitting | D．died; has been sitting |
Susan wanted to be independent of her parents. She tried _____ alone, but she didn’t like it and moved back home.
| A．living | B．to live | C．to be living | D．having lived |
I called Hnnah many times yesterday evening, but I couldn’t get through. Her brother _____on the phone all the time!
| A．was talking | B．has been talking | C．has talked | D．talked |
The flowers were so lovely that they __________ in no time.
| A．sold | B．had been sold | C．were sold | D．would sell |