Experiments of this kind __________ in both the U. S. and Europe well before the Second World War.
| A．have conducted |
| B．have been conducted |
| C．had conducted |
| D．had been conducted |
The number of the people in the room_______sixty, but a number of them_________students.
| A．was, was | B．was, were | C．were, were | D．were, was |
What did he say? I don’t know what________.
| A．did he say | B．he says | C．he said | D．he is saying |
I told your friend how to get to the hotel, but perhaps I______have driven her here.
| A．could | B．should | C．must | D．might |
I’m sorry to have hurt you, but I didn’t do it________.
| A．in common | B．in fact | C．on purpose | D．as usual |
It is the first time that I_______to Beijing.
| A．was | B．have been | C．came | D．will come |