--Where is Xiao Wang?
--I don't know. He__________ be in the library.
| A．can | B．must | C．might | D．may |
After two days of long walk, his strength gave __.
| A．off | B．out | C．un | D．up |
No matter what they say, I’ll ___ my opinion.
| A．stick to | B．persist in | C．insist on | D．hold up |
He ___ to break the record for the long-distance race.
| A．set out | B．set off | C．set up | D．set down |
__ your courage, ___ you will not fail.
| A．Keep to…then | B．Keep up…and | C．Keep up with…and | D．Keep on…so |
He knew nothing about the matter, but he talked as if he __it.
| A．knows | B．knew | C．had known | D．would know |