30. Had it not been for the fact that I _____ absent, I would have asked you to do this right now.
| A．had been | B．were | C．should be | D．Was |
most parents care about is to provide the best education for their children.
| A．What | B．That | C．How | D．Whether |
--- May I smoke here?
--- If you , choose a seat in the smoking section.
| A．should | B．could | C．must | D．may |
The government has taken measuresair quality.
| A．to improve | B．improved |
| C．being improved | D．to be improved |
Thanks to Mr. Smith the father and the son eventually________after ten years' cold relationship between them.
| A．took up | B．made up | C．looked up | D．turned up |
From the dates on the gold coin, we know that it was made 500 years ago.
| A．marking | B．marked | C．to mark | D．to be marked |