You must read this whole article; otherwise, you will not understand anything. Just kidding! But perhaps you should read on if you want to know more about modal verbs.
In the previous two sentences alone, three modal verbs were used! Even if you aren't aware of it, we use modal verbs all the time in both spoken and written communication. They are used before the main verb in a sentence to give more specific information about the modality of that verb.
Modal Verb Definition
Modal verbs are a type of auxiliary verb, meaning they are used before the main verb in a sentence and cannot function alone. Modal verbs are used to show modality, such as: expressing a possibility, ability, or obligation. They can also be used when giving advice or asking permission.
For example, the modal verb "will" can be used to talk about an event that is going to happen in the future, i.e., "she will go to her dance recital."
Fig. 1 - As modal verbs are auxiliary, they are sometimes referred to as "helping verbs."
Modal Verb Infinitive
It is important to remember that modal verbs are used before the main verb in a sentence, as they add more information to the meaning of the main verb. When using a modal verb, ensure you use the infinitive form of the main verb (the form you find in the dictionary) without the "to." For example:
"I will travel to New York next year."
instead of
"I will to travel to New York next year."
Modal Verb Examples
Each modal verb is used for slightly different reasons. Modal verbs can be used positively or negatively to express the probability of something either happening/being possible or not.
Must/must not is used to express complete certainty or obligation.
"Her dad must be a businessman."
"She must practice a lot."
"I must pass my exam."
"I must not fail this test."
"She must not be very tall."
"We must not be discouraged."
Must/must not is also often used to order someone to do/not do something.
"You must pay the fee by December."
"You must all listen."
"You must pay attention to the teacher."
"You must not run inside."
"You must not cheat on the test."
"You must not push in line."
Can/can't is used to show when something either is or isn't possible.
"I can play tennis."
"She can join us."
"They can sing well."
"He can't tie his shoes."
"I can't drive."
"We can't open the door."
Can is also used to ask for permission to do something.
"Can I go out tonight?"
"Can I stay here?"
"Can she join me on holiday?"
Will/won't is used to express whether or not something will occur in the future.
"There will be a party at mine tomorrow."
"I will be on holiday."
"She will start training on Monday."
"I won't be able to make it to the meeting."
"We won't be living together next year."
"They won't win the competition."
Will is also used to make promises and voluntary actions in the future.
"I will help you with your homework."
"I will bake you a cake."
"She will apologize to her friend."
Should/shouldn't is used when you expect something to happen/not happen in the future (but are not 100% sure).
"We should be able to make it to the party."
"I should be able to finish my essay by tomorrow morning."
"They should be home soon."
"I shouldn't be out for too long."
"It shouldn't be too difficult."
"He shouldn't need much time."
Should/shouldn't is also used to give advice. Instead of directly telling someone to do something, using should/shouldn't is less confrontational and leaves room for consideration. Along with the modal verb, adverbs such as probably, perhaps, and possibly are often used to be more polite.
"You should see your doctor."
"You shouldn't smoke."
"Perhaps you should study tomorrow."
Would/wouldn't is used when expressing past or current thoughts about the future, or current feelings about past events.
"I thought I would be driving by now."
"I would love to learn how to play football."
"I would do anything for my family."
"I wouldn't be here now without all the hard work."
"I wouldn't miss the concert for anything."
"I wouldn't be surprised if my friend moved abroad."
May/may not and might/might not are used when the probability of something being possible or true is around 50%.
"He may win the contest."
"She may jump in the water."
"He may not see his brother."
"They may not dance again."
"I might go and see my friends."
"He might buy his dad a present."
"She might not go outside."
"We might not move house."
May is also used to ask for permission, although this is mostly used in formal settings:
"May I sit here?"
"May I use the bathroom?"
"May I have the bill please?"
Could is used when the possibility of something occurring in the future is not 100% certain.
"I could stay home tonight."
"She could catch a cold."
"He could walk to school."
Could is often accompanied by a conjunction, such as "but" to express uncertainty or a reason why something is not 100% possible.
"The answer could be right, but I'm not sure."
"I could tell you, but it's a secret."
"He could stay out, but he needs to study."
Could is also used to ask permission.
"Could I get a glass of water please?"
"Could you pass me the salt?"
"Could we share a room?"
Couldn't is used to show certainty about something in the past that did not happen.
"They couldn't find the keys."
"I couldn't fix my car."
"We couldn't get home."
Modal Verb List
Below is a list of modal verbs:
Must / must not / mustn't
Might / might not
May / may not
Would / would not / wouldn't
Should / should not / shouldn't
Could / could not / couldn't
Can / cannot / can't
Will / will not / won't
Ought to
Fig. 2 - Modal verbs can help us determine the probability of something being possible or true.
Active Modal Verb
Modal verbs can be used with both the active and passive voice. Let's begin by taking a look at the definition of the active voice:
The active voice occurs in a sentence when the subject is actively performing the action of the verb. Sentences written in the active voice follow the structure: subject + verb + object (SVO).
For example:
| Subject | Verb | Object |
| She | holds | the puppy. |
Here is an example of a modal verb being used in a sentence written in the active voice:
| Subject | Modal Verb | Main Verb | Object |
| She | must not | hold | the puppy. |
In particular, the modal verb "must not" is used here to order the subject to not do something. The modal verb always comes before the main verb in a sentence.
Passive Modal Verb
The passive voice is used less than the active voice and is less direct.
The passive voice occurs in a sentence when the subject receives the action of the verb. In this instance, the object assumes the position of the subject.
A sentence written using the passive voice will always contain a form of "to be" and a past participle. It can also contain a preposition (such as "by"), but this is not always needed.
An example structure of a passive sentence is:
| Object | Form of "to be" | Past participle | Preposition | Subject |
| The puppy | is being | held | by | her. |
Here is an example of a modal verb being used in a sentence written in the passive voice:
| Object | Modal | Form of "to be" | Past participle | Preposition | Subject |
| The puppy | must not | be | held | by | her. |
In this case, the modal verb is used before the form of "to be."
Modal Verbs - Key takeaways
- Modal verbs are used to show modality, such as: expressing a possibility, ability, or obligation. They can also be used when giving advice or asking permission.
- Modal verbs are a type of auxiliary verb, meaning they are used before the main verb in a sentence.
- After the modal verb, make sure to use the infinitive form (found in the dictionary) of the main verb without the "to."
- Modal verbs give the main verb a more specific meaning, which helps to determine the probability of something being possible or true.
- Modal verbs can be used in sentences written in both the active and passive voice.
Explanations 
Exams 
Magazine 
