动词按其含义与句子功用,可以分为实义动词、助动词和情态动词.
实义动词（也叫作主动词）意义完全,能够独立作谓语,如：
He lost his job because of automation.
Put the jam on the kitchen table,please.
She had a pain in her side.
The small plane flew low and frightened the livestock.
助动词本身无词汇意义,不能单独作谓语,助动词有do、be、have、will等,它们在句子里与实义动词一起构成各种时态,语态和语气以及否定和疑问结构,如：
Does he have coffee with his breakfast?
Don't be so careless.
The thief was caught in the parking lot.
The child is crying because he has been stung by a bee.
I wish he hadn't gone.
I have known him since 1960.
We won't see him till Monday.
Will you have a meeting tonight?
情态动词词义不完全,不能单独作谓语,必须与实义动词一起构成谓语,有shall、should、will、can、may、must、dare、need、ought to、have to、be going to、be to等.
You should have reported the mater to the police.
A frightened bear will maul campers.
The disease can result in crippling paralysis or even death.
I may have met him before.
You must do some stretching exercises before you attempt to run a mile.
You needn't come so early.
Ann ought to have realized that Joe wouldn't do it.
They daren't tell the truth.
希望我能帮助你解疑释惑.