Whatever you call them (modals, modal verbs, auxiliaries, auxiliary verbs, etc.), modals are one of the most difficult grammar points for students to grasp. We have many categories of modals in English such as possibility, ability, advice, and necessity, and within each category, we have many modals to choose from.
In our American Presidents lesson on Woodrow Wilson, there is an exercise about modals for expressing suggestions. We thought it would be helpful to blog about the modals should, ought to, had better, have got to, have to, and must so that teachers could elaborate on the notes in the lesson.
You could also use this tried‑and‑true method of presenting modals as a lesson on its own, with our Grammar Practice Worksheets or Fun Grammar Lessons on modals, along with another textbook, or for review anytime!
Pattern & Chart
Remind students that the pattern for modals in English is:
Modal + Base Verb
A base verb is an infinitive verb without to. Point out that base verbs never have any endings (no -s, -ed, -ing, etc.), so students don’t have to worry about subject–verb agreement. Make sure you stress to students that they should never use to after a modal (unless it’s a part of the modal expression).
- You must take the exam. (correct)
- You must to take the exam. (incorrect)
- You have to take the exam. (correct)
- You have take the exam. (incorrect)
I always tell my students that for a modal expression that includes to (such as have to), think of to as part of the modal expression and not as part of an infinitive verb (i.e., have to + base verb, not have + infinitive verb). It’s easier for students to remember to never use an infinitive verb with a modal (but they’ll have to remember that some modal expressions include to).
Next, write this “suggestion scale” chart on the board. It’s always helpful when students can visualize where the modals belong in relation to one another.
Using the modal of advice should is the most common way to suggest something to someone in English. The pattern is should + base verb. The negative form, should not, often gets contracted to shouldn’t.
- You should tell your boss about the report.
- They should start getting ready to go because the bus leaves at 4:00.
- She shouldn’t smoke outside because people are eating on the patio nearby.
Ought to is a modal expression that sounds a bit stuffy these days. I always tell my students that though they may occasionally see it in textbooks or in writing, they should avoid using ought to + base verb themselves because it’s pretty old‑fashioned. Some people would argue that ought to is a bit stronger of a suggestion than should, but I’d argue that the difference isn’t important, especially since it’s not commonly used nowadays.
As a general overview (in case students come across it), you may want to mention that in spoken English, ought to is usually shortened to /aw-da/, and that the negative expression ought not to is even less common and best avoided altogether.
- You ought to show your report card to your parents.
Use had better + base verb to make a stronger suggestion than should. This modal of advice is used when someone thinks the other person really should follow the suggestion, implying that there will be more serious consequences if the advice isn’t taken.
Had better is a modal expression that is often contracted to 'd better. The negative form, had better not, is also often contracted to ’d better not.
- We had better let someone know about the problem.
- He’d better study for the test because he’s failing the class.
- I’d better not eat another cookie because I’m on a diet.
Must, Have To, Have Got To
The modals of necessity/obligation must, have to, and have got to have essentially the same meaning and are all used to denote a strong suggestion.
Must + base verb is a little more formal and is often used in written English (e.g., this modal would appear on a sign listing out rules). The negative form is must not. While the contraction mustn’t is possible, it isn’t commonly used nowadays and has a stuffy feel to it. I tell my students to avoid it.
Don’t forget to remind students that can’t/cannot is a modal with basically the same meaning as must not, with can't/cannot being a bit more common.
- You must remove your jacket and shoes when going through airport security.
- We must register for the conference before we can attend any sessions.
- You must not/can’t use a pen. All answers must be written with a pencil.
Have to + base verb is a little more informal and is often used in spoken English and informal writing. Note that this is one modal expression that does have subject–verb agreement. Third person singular pronouns, singular count nouns, and non-count nouns will all use has to + base verb. Point out to students that the contractions 've to and 's to are never possible.
The negative forms, do not have to and does not have to, are often contracted to don’t have to and doesn’t have to.
I always point out that in speaking, have to is often reduced to hafta and has to is often pronounced hasta.
- You have to call your friend tonight. It’s her birthday and she’ll kill you if you forget.
- She has to bring her own skis because there isn’t anywhere to rent them.
- I told my roommate that he doesn’t have to pay for groceries this week because I owe him money.
Have Got To
Have got to + base verb is a very old expression in English that is still commonly used nowadays. It is even more informal than have to and is commonly used in spoken English and informal writing. Note that this is another modal expression that has subject–verb agreement. Third person singular pronouns, singular count nouns, and non‑count nouns will all use has got to + base verb.
The negative forms have not got to and has not got to are never used (do not have to and does not have to can be used instead). The contractions 've got to and 's got to are common in writing, and in speaking, the reduced forms 've gotta and 's gotta are very common in speaking.
- You have got to remember to do your report tonight. It’s due tomorrow morning.
- Our teacher has got to grade a lot of papers tonight. We need them back to study for the test.
- She’s got to go to the doctor’s right after class.
If your students are still confused, they should / had better / have to / have got to / must study more!