Modal verbs also fall under the category of auxiliary verbs as they facilitate the main verb for potential. Ability, permission, expectation, and obligation. If they are used with the main verbs, they will not at any case end with –s for the third person singular. Modal auxiliary verbs are constant and they never change their form but express a different form for the past tense.
The list of modal auxiliaries include:
Must (have to)
Should (ought to) (had better)
|Would (used to)
Should (ought to)
Will – Would
This word expresses a willingness to perform or do something in the future. The negative form of will – will not or won’t express a feeling of unwillingness to perform something.
- This time I will start the semester project early.
- You won’t succeed if you don’t try.
The word would highlight general or frequent willingness in the past. It also specifies the preferences in the present.
- I would be thankful to them if they help me out in the work.
- This movie would be a huge hit.
Can – Could – May – Might
These auxiliary modals portray the ability or possibility of something or someone.
The word can highlight the skill or the ability whereas, could highlight the ability with a choice.
- They can come to my house for studying.
- They could come over and play.
Can and could are also used in a sentence to determine the possibility of something.
- They didn’t win the last time, but I think can do it this time round.
- It could be a great learning curve if you focus.
It expresses the need for something.
- We must complete the work on time.
- Fishes must be in the water in order to live.
Have is of a similar meaning to must as it shows an emergency.
- We have to leave early tomorrow morning.
- He’ll have to study these courses again.
It expresses obligation and probability.
- The teacher asked told them that they should bring their assignments on Monday.
- It’s pretty late, I should leave now.
Should is often replaced with ought to and had better
- I had better wish her or she’ll be upset.
- They ought to allow us to go to the party.