．—Steve come back because the window is open．
—Yes．but he _______left it open last night．
| A．must have；might have | B．might have；can’t have |
| C．can have；should have | D．might；must have |
—Have you seen Rose recently?
— No．It’s five years _____ I met her．
| A．since | B．after | C．when | D．before |
The single most important factor ____ contributes to success is _____ you do every single day．
| A．that; that | B．which; what | C．which; what | D．that; what |
They all looked ____ at the master and felt quite _____．
| A．sad; sad | B．sadly; sadly | C．sad; sadly | D．sadly; sad |
Food prices are climbing around the world because farmers can't ____ demand for grain．
| A．catch up with | B．keep up with |
| C．grow out of | D．put up with |
Most of the professors _____ to our school were from South Africa．
| A．invited | B．to be invited |
| C．being invited | D．had been invited |