What ______ the doctors most was that they could not find the cause of the disease.
| A．astonished | B．puzzled | C．surprised | D．amused |
Our school had about 20 notebook computers but only one-forth_____used regularly. Now we have 50 working all day long.
| A．is | B．are | C．was | D．were |
I can’t say which wine is best, it’s a(n)___ of personal taste.
| A．thing | B．event | C．affair | D．matter |
It was in the lab___was taken charge of by our teacher____ they did the experiment.
| A．which; that | B．where; which | C．which; where | D．that;where |
Our teacher makes good use of any time______ he can spare.
| A．which | B．that | C．when | D．in which |
London,______ last year, is a nice old city.
| A．that I visited | B．which I visited | C．I visited | D．where I visited |