My sister______two hours writing the article yesterday.
| A．paid | B．spent | C．took | D．cost |
We are sure one day the air in Beijing will be much ______ than today.
| A．clean | B．cleaner |
| C．cleanest | D．the cleanest |
What a nice day! We decide ______ out for a picnic.
| A．go | B．going | C．went | D．to go |
— Have ______ cup of coffee, please.
— Thank you.
| A．others | B．other |
| C．another | D．the other |
John ______ leave for New York tomorrow, but I’m not sure.
| A．must | B．may |
| C．could | D．need |
Be careful with the knife, ______ you’ll be hurt.
| A．so | B．or | C．but | D．because |