Grammatical characteristics

Semantic functions of modals

Modals do not express any action or state. They only indicate that the action expressed by the infinitive which follows them is considered by the speaker to be possible, necessary, doubtful, desirable, etc.

Grammatical characteristics

- Modal verbs are followed by a bare infinitive, except for “ought to”.

You may come tonight. You ought to get a job.

- The negative and the interrogative are formed without the help of auxiliaries.

Can I say something? I couldn’t understand him.

- Modal verbs do not take a suffix (-s, -ing or -ed).

He can stay here.

- Modal verbs do not have analytical forms (built by means of auxiliary verbs). Instead, the equivalents of modal verbs are used.

I have never had to make coffee for my boss. (pr. perfect)

- Modal verbs can’t be used as infinitives, gerunds or participles. Instead, the equivalents of modal verbs are used.

I hate having to get up so early every day. (gerund).

We don’t seem to be able to find the book you need. (infinitive) Not being able to go home by bus, I took a taxi. (participle I)

- Modals usually refer to the present or the future. Could, might, would and should are past in form, but do not actually refer to the past in most of their meanings. Could you help me? (polite form) Could he be so silly? (doubt)

There are only a few cases when modals have past reference:

He could ski well when he was young. (ability in the past);

When we were young we would go out together. (past habit);