18．Development of economy ______ which our country attaches great importance, has drawn the attention of the whole world.
| A．with | B．for | C．to | D．in |
We ________the difficulty together, but why didn’t you tell me?
| A．should face | B．might face | C．could have faced | D．must have faced |
He gave the old couple a lot of money and didn’t expect to receive anything ______for them.
| A．in all | B．in fact | C．in return | D．in short |
The math problem seems very easy, but in fact it is very difficult_______.
| A．to work out | B．being worked out | C．working out | D．to be worked out. |
-----What did you think of Mount Tai?
------Wonderful. It’s worth ______once again.
| A．being visited | B．to visit | C．visiting | D．visited |
In the past twenty years, the sad father has been to many places-______his lost son.
| A．in face of | B．in favor of | C．in charge of | D．in search of |