We need modal verbs to express different levels of certainty and possibility. Also, we use them to speak about ability, to make requests and offers, to ask for permission, to express necessity or obligation.
There are 9 modal verbs in the English language. They all have their own meanings and differences in usage. That means, as a rule, we can not use them interchangeably.
At first, here is the list of modal verbs:
❗️ ought to
Some grammarians move the verb 'ought to' to a special place and call it semi-modal. We have dedicated a distinct article to this verb. You can read it here.
In addition, you can find separate articles about certain modal verbs here👇
- Modals of deduction
- Modals of ability
- Modals of obligation and advice
- Modals of permission
- Modals of requests
Now, let's focus on what modal verbs really are, their grammatical functions and general rules.
Modal verbs general rules
Modal verbs do not act like main verbs in a sentence. That is why, some grammarians call them defective. This aspect makes them easy to use. But you need to remember these simple rules of usage of modal verbs:
Look at the examples below 👇
Mike can swim — no ending to show person, no particle 'to' after
Can Mike swim? — forms a question
Modal verbs and tenses
As we have mentioned above, modal verbs don't change their forms to make tenses. Also, we remember that the majority of them refer to the present and the future. Though, there are some of them that can refer to the past.
Then, we have different ways to make up tenses without avoiding modal verbs.
|She says Mike can go to the GYM tomorrow.||Sandra said Mike could go to the GYM the next day.||Mike can go to the GYM tomorrow.|
|Can you give me your pen for a while?||Could you give me your pen for a while? — more polite|
|You may go with Mike if you want.||You might go with Mike if you want. — more formal|
|You should be more attentive.||You should have been more attentive.|
|He must be waiting for us.||He must have been waiting for us for 4 hours.|