Studies have shown that scientists produce not only some of the best ideas, but also _____ bad ones.
| A．a great many of | B．a great deal of |
| C．;a large amount of | D．a great many |
The students _______ busily when Miss Brown went to get a book she _______ in the office.
| A．had written, left | B．were writing, has left |
| C．had written, had left | D．were writing, had left |
I think you must be mistaken about seeing him at the theatre; I’m sure he _____ abroad all week.
| A．is | B．was |
| C．has been | D．had been |
They haven’t arrived yet but we _____ them at any moment.
| A．are expected | B．have expected |
| C．are expecting | D．will expect |
I feel sure I _____ her before somewhere.
| A．was to meet | B．have met |
| C．had met | D．would meet |
You’ll never guess who I met today — my old teacher! We _____ for 20 years.
| A．don’t meet | B．haven’t met |
| C．hadn’t met | D．couldn’t meet |