We thought of selling this old furniture,but we decided to___it.It might be valuable
| A．hold on to |
| B．keep up with |
| C．turn to |
| D．look after |
Thank you very much for the trouble you have taken _________ me with my English.
| A．helping | B．to help | C．help | D．helped |
Before the conference, a new problem came up __________ could speak on behalf of our group.
| A．that | B．who | C．which | D．how |
He dressed up and went to the party as if ___________.
| A．was invited | B．had been invited | C．invited | D．to be invited |
Scientist are not sure about the ___________ of water on the Mars.
| A．occupation | B．existence | C．demand | D．treasure |
Don’t push me! __________ you know the truth right away?
| A．Must | B．Could | C．Might | D．Would |