How did it______ that humans speak so many different languages?
| A．come out | B．come off | C．come about | D．come round |
. 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 |
It isn't so much whether he works hard; the question is whether he works _____.
| A．above all | B．in all | C．at all | D．after all |
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 |