All the students in our class buried themselves ________studies，________
the coming exam.
| A．in；preparing |
| B．in；preparing for |
| C．for；prepared |
| D．for；prepared for |
In aerospace devices the weight of the necessary power producing equipment is _____.
| A．vital | B．possible | C．capable | D．reliable |
Stressful environments lead to unhealthy behaviors such as poor eating habits, which _____ increase the risk of heart disease.
| A．in turn | B．in return | C．by chance | D．by turns |
The family is a cooperative enterprise for which it is difficult to _____ rules, because each family needs to work out its own ways to deal with its own problems.
| A．set up | B．put down | C．keep up | D．lay down |
I'd like to take _____ of this opportunity to thank you all for your cooperation.
| A．profit | B．benefit | C．advantage | D．interests |
I could tell he was surprised from the _____ on his face.
| A．appearance | B．view | C．sight | D．expression |