It is dangerous to allow the children who are ________ swimming in the river.
| A．enough old to go | B．not old enough to go |
| C．not enough old to go | D．not old enough going |
The new library building _____ last week.
| A．was completed | B．is completed | C．completed | D．has completed |
—Did you call Sara back?
—I didn’t need to, _____ we’ll have a meeting together tonight.
| A．though | B．unless | C．because | D．if |
Keep practicing and you _____ your English.
| A．improve | B．will improve | C．improved | D．were improving |
The air in mountain areas is ____ that in big cities.
| A．as fresh as | B．fresher than | C．as dirty as | D．dirtier than |
Beijing is _____ capital of China and it is _____ city with many places of interest.
| A．a; a | B．a; the | C．the; a | D．the; the |