• 表示“需要”时为实意动词,后面可以加名词,也可以加不定式:

I need a pen.
Do you need any beer? No, I don’t.
I need to have a rest.

Need doing=need to be done (表示被动)

The flowers need watering. =The flowers need to be watered. 花需要浇水。

• need在否定时做情态动词使用:

You needn’t go so early. (=You don’t need to go so early.)
Must I clean the desk right now? No, you needn’t.