Cambridge Grammar of English Hardback with cd-rom a comprehensive Guide

Semi-modal need and lexical verb need

397a

The meanings of semi-modal need and the lexical verb need often overlap and

lexical verb need can often be used as an alternative to semi-modal need:

Fishing is dangerous – but 

need it be this dangerous? 

(or: Fishing is dangerous – but does it need to be this dangerous?) 

[lecturer to students]

There is an intimate link between the presence of the virus in these cells and

the production of the tumour. We 

needn’t take the figures down here, erm, but

what this shows is the second transforming virus, which is hepatitis B virus. 

(or: We don’t need to take the figures down …)

✪

The full lexical verb to need, not the semi-modal need, must be used when the

verb complement is a noun phrase or noun-phrase equivalent (e.g. an -ing

clause):

You 

don’t need an invitation.

(You needn’t an invitation.)

The hedge 

doesn’t need cutting.

(The hedge needn’t cutting.)