The achievements of the greatest minds in science could never have been reached________ the patient work of hundreds of others．
| A．were it not for | B．had it not been because |
| C．had it not been for | D．if it had not been |
We went to Mountain Tai last weekend, ________, not surprisingly, was crowded with visitors.
| A．that | B．which | C．where | D．when |
The town _______ we visited last month is the one _______ the famous painter was born.
| A．where; which | B．which; where |
| C．which; that | D．where; where |
The opening ceremony is to be held in the lecture hall this afternoon, _____ can seat 400 people.
| A．where | B．when | C．that | D．which |
It is reported that no problems have been discovered in milk products such as Yili, Sanlu and Mengniu, ________ proves newly-produced liquid milk safe.
| A．that | B．what | C．which | D．where |
Was __ at the air battle on June 8,1994, ____ was led by Captain Johnson ___ Peter lost his life?
| A．it; when; that | B．that; that; who | C．it; which; that | D．it; which; when |