RULES OF MODAL VERBS
| No. | Rule | Example |
|---|---|---|
| 1 | Modal verbs are helping verbs that express ability, possibility, necessity, or permission. | He can swim well. |
| 2 | Modals do not change with subject. | She can run, / They can run. |
| 3 | Common modals: can, could, may, might, must, shall, should, will, would. | He might come tomorrow. |
| 4 | Modals are always followed by the base form of the verb, | You must study. |
| 5 | Modals have no -s, -ing, or ed forms, | X He cans sing. / He can sing, |
| 6 | Modals have no infinitive forms. | X to must |
| 7 | Modals have no participle forms. | X musting |
| 8 | Modals are the same for all persons. | I can, you can, he can |
| 9 | Modal + be + verb-ing = possibility of ongoing action. | She may be studying now. |
| 10 | Modal + have past participle = past possibility/necessity. | He should have arrived by now |
| 11 | "Can" expresses ability in the present or future. | I can ride a bike. |
| 12 | "Can" expresses informal permission. | You can go now, |
| 13 | "Could" expresses past ability. | When I was young, I could run fast. |
| 14 | "Could"' is used for polite requests. | Could you help me? |
| 15 | "Cann and "Could" are used to ask permission. | Can I use your pen? / Could I &orrow your book? |
| 16 | "May" expresses formal permission. | You may enter now. |
| 17 | "May" also expresses possibility. | I may go to the party. |
| 18 | "May" is more polite than "can" in formal requests. | May sit here? |
| 19 | "Might" expresses weak possibility. | It might rain later. |
| 20 | "Might" is more tentative than may. | He might join us later. |
| 21 | "Might" and "could" are weaker than "may." | It might/could rain today. |
| 22 | "Must" expresses strong necessi or obligation. | You must wear a seatbelt. |
| 23 | "Must" is used for logical certainty. | She must be tired after work. |
| 24 | "Must" is stronger than "should." | You must stop smoking. |
| 25 | "Shall" expresses future (British English, formal). | I shall return soon. |
| 26 | "Shall" is often used with '[I/we" in formal offers. | Shall we dance? |
| 27 | "Shall" is often used in legal or formal documents. | The tenant shall pay rent on time. |
| 28 | "Should" expresses advice or mild obligation. | You should sleep early. |
| 29 | "Should" is used for giving suggestions. | You should eat more fruits. |
| 30 | "Will" expresses simple future. | I will call you tomorrow. |
| 31 | "Will" expresses certainty. | She will pass the exam. |
| 32 | "Would" is the past form of "will." | He said he would help me. |
| 33 | "Would" is used in polite offers. | Would you like some tea? |
| 34 | "Would" expresses habitual actions in the past. | Every summer we would visit our grandparents. |
| 35 | "Ought to" is similar to; "should." | You ought to respect elders. |
| 36 | "Need not" shows lack of necessity. | You need not worry. |
| 37 | "Dare" can act as a modal for challenge. | How dare you speak like that? |
| 38 | Negative forms use "not" directly after the modal. | She cannot (can't) swim. |
| 39 | Questions use inversion of subje and modal. | Can you dance? |
| 40 | "Might have" shows a possibility in the past. | He might have missed the train |
| 41 | "Should have" shows a duty not done in the past. | You should have studied harder. |
| 42 | "Could have" shows unrealized past ability, | I could have won the race. |
| 43 | "Would have" shows unrealized past action. | I would have helped if I had known. |
| 44 | "Must have" shows strong past deduction. | She must have forgotten. |
| 45 | "Can't have" shows strong negative deduction. | He can 't have stolen the money. |
| 46 | "May have" shows uncertain past possibility. | He may have called earlier, |
| 47 | "Might have" expresses less certainty than 'i may have." | She might have left already. |
| 48 | "Need not have" means something unnecessary was done. | You need not have bought so much food. |
| 49 | "Can't" is used for impossibility. | That can't be true, |
| 50 | Mastering modals improves accuracy and politeness in communication. | You should learn modal rules well. |