Listen to the laughter, the girls _______themselves.
| A．may enjoying | B．can be enjoying |
| C．must have enjoyed | D．must be enjoying |
---- Let’s go to cinema.
---- That’ll take your mind off the problem for while.
| A．the; the | B．the; a | C．a; the | D．a; a |
The job was a great challenge and the bad weather _________ our difficulties．
| A．added to | B．added | C．added up to | D．added in |
It is said that this is the biggest lab ________ they have ever built in their school.
| A．which | B．what | C．不填 | D．where |
In order to attract more customers, many supermarkets usually sell their goods at a good________ at weekends.
| A．benefit | B．discount | C．interest | D．cost |
It will be at least three weeks________ he recovers from his illness and returns to work.
| A．before | B．when | C．since | D．after |