may
1.表示“请求许可”，意为“可以，可能”，其一般疑问句否定回答为mustn’t。
—May I go out and play football? —No,you mustn’t.
2.表推测，意为“可能”。如：Mr.Li may be at home.
can(could)
1.表示“能力”，意为“能，会”，否定形式为can’t,couldn’t。
Mike can speak a little Chinese.
/I could ride the bike when I was 6 years old.
2.表推测，常用在否定句和疑问句中。
He can’t be at home. He has gone to Japan.
3.用在疑问句中，表示“征求意见”，could比can的语气更委婉、客气。
Could you tell me something about your school?
4.can用于一般现在时及一般过去时两种时态，
be able to可以用于各种时态。
He can spell these words.
/He has been able to draw pictures already.
must
1.表示义务、命令或要求，意为“必须，应该”，
否定形式mustn’t，意为“不应该,不允许”，表示警告。
You must be careful next time./You mustn’t take photos here.
2.表示推测，意为“必定”。
He must be in the room.
3.表示说话人的主观看法。I must go home now.
4.must引导的一般疑问句，肯定回答用must，have to
否定回答用needn’t或don’t have to。
—Must I finish the homework today?
—No,you needn’t/you don’t have to.
need
1.表示“需要”，多用于否定句。
He needn’t worry about it.
2.作实义动词，后接动词不定式。
I’m very tired and I need to have a rest.
常
见
连
系
动
词
用
法
1.be，是 例： I’m a girl with short hair.
2.become成为，变得
例：Mike becomes interested in Chinese.
3.turn,get,grow 变得
例：Mr. White’s face turned red.
The weather is getting bad.
4.stay，keep保持
The shop stays open till 8 pm. //The girl keeps silent all the time.
5..感官系动词
smell 闻起来， The flowers smell nice.
sound听起来， The plan sounds good.
taste尝起来， The soup tastes delicious.
feel感到，摸起来，The coat feels very soft
look看起来， My mother looks very young.
