.
About 71% of the earth’s surface ______ covered with water, but 20% of the world population ______ have access to safe drinking water.
| A．is; doesn’t | B．are; don’t | C．are; doesn’t | D．is; don’t |
Before he volunteered to direct traffic, Timoteo _________ lots of jobs.
| A．had had | B．has |
| C．have had | D．had |
—I looked after a group of fifteen French children.
—That _________ easy!
| A．mustn’t be | B．mustn’t have been |
| C．can’t have been | D．wasn’t |
Let him _________ ; he is a man of _________ temper.
| A．alone; variable | B．lonely; various |
| C．alone; various | D．lonely; variable |
With a lot of difficult problems _________ , the newly-elected president is having a hard time.
| A．settled | B．settling |
| C．to settle | D．being settled |
_________ much I practice, I shall never win an Olympic gold medal.
| A．Although | B．However |
| C．Whatever | D．Though |