At present ________ of the experiments ________done in labs after the new building has been finished.
| A．four fifth; is | B．four fifths; are |
| C．four fifth; are | D．four fifths; is |
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 |
Jack almost fell off the cliff, but managed to _____ until help came.
| A．keep on | B．catch on | C．count on | D．hang on |