Modals in English grammar are used with a main verb to add further meaning to the sentence. They show things such as possibility, ability, regret, or necessity.
In this lesson we'll explain the form of modal verbs and then their function with examples.
Modal verbs are auxiliary verbs (helper verbs) formed by placing them in front of the main verb in a clause. They will not tend to appear on their own, unless it's clear from the context what it means.
These are the main rules. They:
This is the basic structure:
Here are some examples of modal verbs in use with main verbs.
You'll have noticed from the examples that some of the modal verbs had 'to'. There are several modals in English grammar that have some exceptions to some of the rules above, and they are called semi-modal or marginal modal verbs.
They have some of the grammatical characteristics of 'pure' modal verbs. One of the basic differences is that most are followed by the infinitive (i.e. with 'to') rather the bare infinitive.
Another marginal modal in English grammar is had better, which is different because it is made up of two words.
These marginal modals can differ in the way they are made negative or interrogative. We'll look in more details at these in another lesson that will be coming soon.
Most modal verbs can also be used in the past. When we do this, we add have + past participle after the modal verb.
Modals in English grammar are used with a main verb to change its meaning. Take a look at this example:
The first one is just a factual statement. The person does their homework each night. However, the second one by using 'must' is showing that the person has no choice in this - it's an obligation, for whatever reason.
There are a variety of modals in English grammar and each one differs in how they change the meaning of a sentence. Some can have more than one use. We'll now look in more details at when we use them.
These are used to indicate the possibility, probability, or impossibility of something happening or being true.
Learn more about modals of possibility >>
The modal can is used to show what someone is able to do, whereas can't or cannot show what someone is unable to do. For the past, could is used.
Being a marginal modal verb, be able to is a modal in meaning but not form. It has the verb to be so can be used in different tenses.
Learn more about modals of ability >>
The modal can is also used to ask for permission. Could is also used as a polite form of this, as is may.
Can is slightly less polite than the others.
Should and had better are by far the more common than ought to. Should tends to be used over Ought to or had better to make questions.
Though need to has been placed here, it could feasibly be placed as a modal of suggestion/advice as it's not quite as strong as must or have to.
Will is used for habits in the present or future, while would and used to are used for past habits - used to specifically for habits that have stopped.
Regrets are things from the past that we wish we'd done differently now, so the past form of the modal is always used: modal + have ('ve) + past participle.
Take a Modal Verbs Quiz >>
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