Shortly after the accident, two ___________ police were sent to the sport to keep order .
| A．dozens of | B．dozens | C．dozen | D．dozen of |
The wild flowers looked like a soft blanket _______the desert.
| A．covering | B．covered | C．cover | D．to cover |
When ____ about the source of his income, he hesitated for a moment, obviously not willing to give us a direct answer.
| A．asked | B．asking | C．being asked | D．having asked |
In the past few months, a discussion ________about whether selecting “Three Goods” Students in elementary and middle schools should be cancelled.
| A．has to be held | B．has been held |
| C．has been holding | D．was held |
—How much do you know about the 3D film technology?
—A little. Not until _______the hot movie Avatar _______ some about it.
| A．did I see; did I begin to learn | B．I saw; I began to learn |
| C．I saw; did I begin to learn | D．did I see; I began to learn |
The expo is being held in Shanghai, _______a lot of advanced technology is shown for the first time.
| A．why | B．which | C．when | D．where |