Need is used both as an ordinary verb and as an auxiliary verb. As an ordinary verb need is used in the sense of require. The ordinary verb need has -s in the third person singular. Questions and negatives are made with do.
- Do you need any help?
- We need more volunteers.
- We have got what we needed.
- I need more time to decide the question.
- He needs our help.
The auxiliary verb need remains unchanged, whatever be the number or person of the subject. It is common in negative clauses. It does not have -s in the third person singular.
- You need not wait.
- He need not ask my permission.
- They need not make such a fuss over it.
The auxiliary need is sometimes used with hardly.
- We need hardly say that we are very grateful.
- I need hardly say that you are always welcome.
It can also be used with only.
- You need only sign this paper and I will do the rest.
The auxiliary need is usually used in questions without ‘not’.
- Need we wait any longer?
- Need I come again?
If the answer is in the negative, say ‘No, you need not.’ If the answer is in the positive, say – ‘Yes, you must.’
When referring to past time, need is followed by the perfect infinitive (have + past participle).
- We need not have waited for them.
- We need not have wasted our time and energy on that project.
- You need not have lost your temper.