1、实意动词：1. need sth.
They need a change.
2. 肯：need to do sth. 否：don't need to do
I need to get some sleep.
3. need doing/ to be done
The flowers need watering/ to be watered.
2、情态动词：肯：need do 否：needn't do
You needn't finish that work today.
3、名词：There is no need for sb. to do sth.
meet a need
4、needn't have done 本不必做实际上做了
We brought some food to the party but there was too much, so we needn't have brought any.
5、didn't need to do 本不必做实际上没做
My friend spoke good Mandarin so I didn't need to translate the speech for him.
6、练习：
1. The office had already opened when we arrived so we _______________ (wait) outside in the street.
2. I got to the party at 6 p.m. but there was no one there, so I _____ (arrive) so early.
3. I told the host all about my home town and then he told me he's been there. I _____(tell) him anything!
