Grammar: Word classes: Verbs: Verb formation

Modal auxiliary verbs (can, could)

What are modal auxiliary verbs?: Student problems

Students have difficulty with the form of the main lexical verb following a modal verb. Some students use the full infinitive instead of the bare infinitive:

	You should to eat vegetables and meat.
	You should eat vegetables and meat.

Other students attempt to use a past tense form of the main lexical verb:

	I must finished my homework before she comes back.
	I must finish my homework before she comes back.

Some students do not realise that will is an auxiliary verb, and must be followed by a full lexical verb:

	I will [ ] to the manager of Park'n'shop.
	I will talk to the manager of Park'n'shop.

Many students think that would can be used in the same way as will to indicate future meaning. It cannot:

	I am glad to hear that you will be coming to Hong Kong next month with your parents ... I think you would have a very happy holiday.
	I think you will have a very happy holiday.

You use the modal verb will in the following situations: if you want to indicate definite intentions; if you are making predictions about the future; as well as when you ask, agree or promise someone to do something.

Mr Wong will be late tomorrow.