---- Did Mary come to the party?
---- I don’t know. She _____ while I was out.
| A．might have come | B．might come | C．should have come | D．must have come |
The company earned a lot of money. As a result, the members’ personal income rose by a/an __ of 13 percent.
| A．average | B．ordinary | C．common | D．usual |
With the help of high technology, more and more new substances ___in the past few years.
| A．discovered | B．have discovered |
| C．had been discovered | D．have been discovered |
It was dark. We decided to ___for the night at a farmhouse.
| A．put down | B．put up | C．put away | D．put on |
They would __if food was difficult to find, so they celebrated when they had food.
| A．kill | B．disappear | C．starve | D．start |
It was the woman ___had been in prison __stole the money.
| A．who; where | B．that; how | C．who; who | D．that; where |