The guest room_______.
A. needn’t to be cleaned
B. doesn’t need cleaning
C.needs not to be cleaned
D.needn’t cleaning

1) modal verb.
need do
Needn’t do
Need sb do ….?
Needn’t sb do……?
2)Verb.
Need to do
Needs to do
Needed to do
Doesn’t need to do
Do sb need to….?
Doesn’t sb need to…?
The guest room_______.
A. needn’t to be cleaned
B. doesn’t need cleaning
C.needs not to be cleaned
D.needn’t cleaning
Parse:A:needn’t be cleaned(modal verb)
doesn’t need to be cleaned(verb.)
B: doesn’t need to be cleaned=doesn’t need cleaning（need doing=need to be done, 实义动词）
The machine needs repairing.
=The machine need be repaired.(modal verb.)
=The machine needs to be repaired.
C:doesn’t need to be cleaned
D.needn’t to be cleaned(modal verb)
Needn’t doing(x)
(B)