As well as making simple statements or asking questions, we may sometimes want to express our intentions and attitudes, talk about necessity and possibility, or make offers, requests, or suggestions. In English these uses of language are usually expressed by a set of verbs called modal verbs. The most commonly used modals in English are:
The main characteristics of modal verbs are the following:
1. Modals are always followed by the base form of the verb.
He can play the guitar brilliantly.
2. Modals do not take suffixes, i.e.: they have no –ing or –ed forms, and do not take –s in the third person singular present.
They may come to visit us tonight.
Unlike other verbs, modals do not use do and did to form negatives. Negatives are formed by putting not immediately after the modal, except in the case of ought to, where the negative form is ought not to (which is sometimes abbreviated to oughtn’t to). The negative of can is written as one word cannot, more usually shortened to can’t. Shall not and will not are usually abbreviated to shan’t and won’t Could not and would not usually appear as couldn’t and wouldn’t.
They might not come to visit us tonight.
You ought not to go to work for a week.
They can’t swim.
We won’t go out unless the weather is good.
Modals do not use do and did to form questions. Questions are formed by placing the modal before the subject. In the case of ought to, ought is placed before the subject and to after it.
Can you lend me some money?
Ought you to help them?
They do not form all tenses. They usually have present or past tense.
Mary can ride a bicycle. (present tense)
Mary could ride a bicycle when she was five. (past tense)