1.need用作情态动词
need用作情态动词时,后接动词原形,一般用于否定句和疑问句中,没有人称,数和时态的变化。肯定回答用must,否定回答用needn't或don't have to。
You needn't hurry. We have plenty of time.你不必着急。我们有足够的时间。
--Need I go with you tomorrow?我明天需要和你一起去吗?
--Yes, you must. 是的,你必须去。
--No, you needn't/ you don't have to.不,你不必去。
2.need用作实义动词
①need用作实义动词时,后接带to的不定式,有人称和数的变化,疑问式,否定式需要助动词do构成。
He needs to look after his son everyday.他每天都需要照顾他的儿子。
He was too sleepy, so he needed to get some sleep.他太困了,所以他需要睡会儿觉。
Do I need to stay here to help you?需要我留下来帮你吗?
You don't need to leave yet, do you?你不必现在就走吧?
②need用作实义动词,后接名词,代词,动名词等。
I really need your help.我真的需要你的帮助。
The flowers need watering/to be watered.这些花需要浇水。
重点提示:一般来说,当主语为物时,need后跟doing或to be done,表达的含义相同。
③needn't have done 本没有必要做某事(暗含有本来没有必要做某事,但实际上做了)
You needn't have come so early, for the meeting will be two hours later.你本来不必来得这么早,因为会议将在两小时后举行。
in need 在危难中;在穷困中的
need for 对……的需要;需要……
in need of 需要…时
no need 不需要;不必了
need to do 需要做…
urgent need 迫切需要
need help 需要帮助
actual need 实际需要