2. Choose the words to complete the sentences.
“must、mustn’t、can、can’t”.
We talk loudly in the library.
You eat too much sweet food.
They wait under the big tree.
You keep your classroom clean.
You plant more trees to keep the air clean.
You run quickly on the road.
Summary:情态助动词can, must的用法:
can: 能,可以。Can’t: 不能,不可以,是否定形式。后面都接V原形.
Must:必须,一定,mustn’t: 禁止。后面也加V原形。Must….?回答:Yes, sb. must. No, sb. needn’