______ I admit that there are problems, I don't agree that they cannot be solved.
| A．As | B．If | C．While | D．When |
The government placed _____ on the numbers of foreign cars that could be imported.
| A．limitations | B．restraint | C．requirements | D．restrictions |
He ate what he could, and gave the _____ of the food to the birds.
| A．remain | B．uneaten | C．rest | D．part |
Mary had taken _____ to see that her guests had everything that they could possibly want.
| A．efforts | B．pains | C．attempts | D．endeavors |
Expected noises are usually more _____ than unexpected ones of the like magnitude.
| A．manageable | B．controllable | C．tolerable | D．perceivable |
Experts say walking is one of the best ways for a person to _____ healthy.
| A．preserve | B．stay | C．maintain | D．reserve |