The verbs can, may must, ought, shall, should, will, would, need and dare form a special class of verbs, which are called modal verbs.
MV also have follow pecularities:
Do not take -s at the 3d person singular
Do not take ending -ing or -ed
Go before the subjects in questions and are followed by 'not' in negations
Do not usually have tenses
All of them (accept OUGHT TO and sometimes DARE and NEED) are followed by the infinitive without the particle 'to'
All of them (accept DARE and NEED) form the negative and interrogative forms without the axullary 'do'
Modal verbes are used with the infinitive of another verb
MV denote neither actions, nor states; they show that the action or state denoted by the infinitive is considered as possible, obligatory, necessary, desirable, probable, doubtful, allowed, advisable, etc.
