If you smoke, please go outside.
| A．can |
| B．should |
| C．must |
| D．may |
In order to find _______ better job, he decided to study _________ second foreign language.
| A．the; a | B．a; a | C．the; the | D．a; the |
The biggest whale is ___ blue whale, which grows to be about 29 meters long—the height of ___ 9-story building.
| A．the; the | B．a; a | C．a; the | D．the; a |
We can never expect bluer sky unless we create less polluted world.
| A．a; a | B．a; the | C．the; a | D．the; the |
Some people fear that ________ air pollution may bring about changes in _______ weather around the world.
| A．/; the | B．the; / | C．an; the | D．the; a |
This area experienced. heaviest rainfall in month of May.
A. 不填; A. B. a; theC. the; theD. the; a