This lesson is in two parts. Part 1 explains the grammar of modal verbs and where they are placed in a sentence or question. Part 2 explains the meaning of each modal verb and provides example sentences.
One reason modal verbs are difficult for students to master is that their meanings change depending on the context. Sometimes, two, three, or even four modal verbs can mean the same thing. This page defines each modal verb and provides example sentences to give an idea of what they mean in context. Be aware that only a few examples for each modal verb can be given here. While usage and differences can often be subtle, this lesson will provide a general idea of how and when to use modal verbs.
Remember, English has ten modal verbs.
The modal verb can is indicates ability or possibility.
|Birds can sing.|
|We can speak English.|
|I can take you to the train station.|
|Ideas can change.|
In questions, the modal can is used to request permission to do something or to ask about possibilities.
|Yes / No questions||Can I help you?|
|Can Tom eat dinner with us?|
|Wh– questions||Who can answer the question?|
|When can we have the results?|
The modal could is used to indicate possibility now.
|I could eat three pizzas. (I am very hungry)|
|This could be my big chance. (this is an excellent opportunity)|
The modal could + have is used to indicate an unrealized possibility in the past. These examples resemble the conditional (explained below) because there is an implied “if” clause.
|implied if clause|
|I could have told you that.||(if you had asked me)|
|It could have been a disaster.||(if they had lost control)|
|The rain could have ruined the party.||(if we had been outdoors)|
Note that can indicates an ability in the present while could indicates an ability in the past.
|present||I can speak French.|
|(I know how to speak French at this moment.)|
|past||I could speak French when I was young.|
|(In the past, I spoke French. Now, I am unable to speak it.)|
The modal verb could is used to speculate about future possibilities. In the following examples could and might are synonomous.
|It could / might rain tonight.|
|This could / might be dangerous.|
In Yes / No questions, could is used to speculate about present of future possibilities.
|Could she be the assasin?|
|Could this be a mistake?|
|Could you return tomorrow?|
Could and can indicate a range of options (hypothetical possibilities).
|We could / can go see a movie, or we could / can stay home.|
|I could / can become a doctor, or I could / can become an artist.|
The modal could is also used to make requests. In these examples could and can are synonymous but could is more polite.
|Could / Can you open the window?|
|Could / Can you help me move this sofa?|
The modal verb could is very important in the formation of conditional sentences. Note there are two clauses: one clause contains the modal could and the other is the result clause. In these situations, could is used to express hypothetical results.
|If we leave sooner, we could take the train.|
|I could pass the test if I study more.|
Could is also used to make conjectures about past hypothetical results. The results were not realized because a particular condition was not met.
|If we had left sooner, we could have taken the train.|
|I could have passed the exam, if I had studied more.|
|I’m glad we took umbrellas. We could have gotten soaked.|
The modals will and shall are used to talk about the future. These modals indicate an intention or an action that is expected to happen in the near or distant future. When used in this type of phrase, there is no difference in meaning between these two modals; however, shall is rarely used in American English.
|I will / shall close the door for you.|
|Tom will / shall meet us at the train station.|
|They will / shall graduate in two years.|
In wh- questions, will and shall are used to ask about future possibilities.
|Who will / shall drive the car?|
|What time will / shall we meet?|
|When will / shall I see you again?|
In yes-no questions, will is used to ask a favor and shall is used to offer a favor. Note that the modal verb will is used with the second person (singular and plural) while shall is used with the first person (singular and plural).
|2nd pers.||Will /
|| Will /
Will is also used to ask for information about a likely possibility regarding somebody or something.
|Will you stay in a hotel?|
|Will good triumph over evil?|
Shall is used to ask about a preference. In these examples, shall and should are synonymous. However, in American English, shall is rarely used. Remember, in questions shall is only used in the first person singular and plural.
|Should / Shall I stay here?||Should / Shall we stay here?|
|2nd pers.||Should /
|3rd pers.||Should /
The modals may and might are used to indicate an uncertain future action. These two modals are synonymous.
|I may / might go to the park, or I may / might stay home.|
|This may / might be a bad idea.|
|It may / might rain tonight.|
The modal verbs may or can are used to give instructions or permission. May is more polite.
|You may / can now board the airplane.|
|They may / can begin the exam in one minute.|
The modals may, can, and could are all used in Yes-No questions to make requests. May and could are more polite than can.
|May / Can / Could I see your passport?|
|May / Can / Could we have some more water, please?|
Sometimes the modal verb might is used in place of may, can, or could, but this is rare in American English.
|May / Can / Could / Might I be of some assistance?|
|May / Can / Could / Might we offer you a suggestion?|
The modal must is used to indicate a recommendation or an obligation.
|You must see this movie.|
|Tom must see a doctor immediately.|
Must is also used to indicate an assumption.
|My watch must be broken.|
|Tom must have left. He is not here.|
In Wh– questions, must is used to indicate an obligation and can be replaced with the modal should. In American English, should is much more common in this context.
|more common||=||less common|
|When should we be there?||When must we be there?|
|Who should I talk to?||Who must I talk to?|
The modal verb must is sometimes used to form rhetorical questions, especially when you want a person to stop doing something.
|Must you make so much noise?||=||Please be quiet.|
|Must he be so cruel?||I wish he were kinder.|
The modals should and ought are used to indicate an obligation. In this context, these two modals are synonymous. Remember, ought is the only modal verb followed by an infinitive.
|You should call your mother.||You ought to call your mother.|
|I should go home now.||I ought to go home now.|
In questions, the modal should is used to ask if an obligation exists. Ought is never used in questions in American English.
|Yes / No questions|
|Should he call her?|
|Should we pay now?|
|Wh– questions||When should we leave?|
|What should I wear?|
The modal verb would, followed by like, is a polite way of stating a preference.
|We would like a table for two.|
|I would like a glass of white wine.|
In questions, would + subject + like is a polite request for you to make a choice.
|Where would you like to sit?|
|Would you like to start with a salad?|
The modal would can make a request sound more polite.
|less polite||more polite|
|Come here, please.||Would you come here, please?|
|Stop making that noise.||Would you stop making that noise?|
Would is used to explain a possibility which is a result of a hypothetical or real condition.
|She would be surprised if you came to the party.|
|I would go with you if I didn’t have to work.|
|I would have arrived sooner if I had not lost my keys.|
The modal verb would is used to introduce habitual actions in the past.
|When I was a student, I would swim every day.|
|When Tom lived in France, he would write me letters in French.|
For details on the placement of modal verbs in sentences and questions, see Modal verbs – part 1.