一、单选
1. _______is often the case in science, there is no simple answer.
A. As B. That C. When D. Where
2. _______my college years soon coming to an end, I have to decide what I want to do after I graduate.
A. During B. With C. For D. Since
3. We were finally able to make the customers _______of the quality of the refrigerator.
A. to convince B. convincing C. convince D. convinced
