_____ private cars are bringing us convenience, they may also cause more traffic accidents and pollution.
| A．While | B．As | C．If | D．Since |
He is only thirty, but has got _____.
| A．a few grey hairs | B．a few grey hair | C．a little grey hair | D．a little grey hairs |
When _______a hand, one should say “Thank you” or “It’s very kind of you.”
| A．offered | B．to offer | C．to be offered | D．offering |
Some students think it is ___ to spend some time surfing the Internet, but we shouldn’t be too dependent on it.
| A．worth | B．worthwhile | C．worthy | D．worthy of |
Not until his mother came back_______.
| A．he began to do his homework | B．had he began to do his homework |
| C．he had begun to do his homework | D．did he begin to do his homework |
—What made Tom so sad? —_______.
| A．His bicycle had been stolen | B．His bicycle to be stolen |
| C．His bicycle’s being stolen | D．His bicycle was stolen |