1. Definition & Key Features
2. Full List of Core Modal Verbs (with uses, examples, teaching notes)
3. Semi-modals (with forms, uses, differences)
4. Special Teaching Tips for TEFL learners

---

🟦 1. What are Modal & Semi-Modal Verbs?

• Modal verbs are auxiliary verbs that express necessity, possibility, permission, ability, obligation, probability, advice, etc.
• They are defective verbs:

  • no -s in 3rd person (He can, not He cans)
  • no infinitive (to can ❌)
  • no past participle (I have musted ❌)

• They are followed by a bare infinitive (must go, can swim).
• Semi-modals are verb phrases that function like modals but are not “pure” modals. They usually combine a normal verb with to or do-support.
  Examples: have to, need to, be able to, be supposed to, ought to, used to, dare (to).

---

🟦 2. Core Modal Verbs 

🔹 CAN / COULD

• Ability:

  • I can swim.
  • She could run fast when she was younger.

• Permission:

  • You can borrow my book.
  • Could I leave early? (polite)

• Possibility:

  • It can be dangerous.
  • That could be his sister.

• Requests:

  • Can you help me? (informal)
  • Could you help me? (polite)

👉 Teaching note: Can = ability/permission; Could = past ability, polite requests, tentative possibility.

---

🔹 MAY / MIGHT

• Permission (formal/polite):

  • You may enter.

• Possibility:

  • It may/might rain later.

• Speculation:

  • That may/might be true.

👉 Teaching note: May is more formal; Might often sounds less certain.

---

🔹 MUST

• Strong obligation (speaker-imposed):

  • You must wear a seatbelt.

• Logical deduction:

  • He must be tired. (certainty)

👉 Teaching note: Stronger/more formal than “have to.” No past tense — use “had to” instead.

---

🔹 SHALL / SHOULD

• Shall (mainly BrE, formal, rare in AmE):

  • Shall we dance? (suggestion)
  • I shall return. (formal promise, older style)

• Should:

  • Obligation/advice: You should see a doctor.
  • Expectation: He should be here soon.

👉 Teaching note: Focus on “should” for advice, “shall” is less practical except in formal contexts.

---

🔹 WILL / WOULD

• Will:

  • Future: She will call later.
  • Spontaneous decisions: I will help you.
  • Promises: I will always love you.

• Would:

  • Polite requests: Would you mind helping me?
  • Hypotheticals: I would travel more if I had money.
  • Past habits: When I was young, I would play outside.

👉 Teaching note: Contrast Will (future fact/intention) vs Would (hypothetical/polite).

---

🔹 OUGHT TO

• Obligation/advice:

  • You ought to eat more vegetables.

• Deduction (less common):

  • Prices ought to fall soon.

👉 Teaching note: Similar to “should,” but slightly more formal/old-fashioned.

---

🔹 NEED / NEEDN’T

• As modal:

  • You needn’t worry. (no -s, bare infinitive)

• As main verb:

  • She needs to work harder.

👉 Teaching note: Teach contrast: “needn’t” = no necessity, vs “don’t need to” (same idea, more common in modern English).

---

🔹 DARE (TO)

• As modal (rare):

  • He dare not speak.

• As main verb:

  • He dares to challenge her.

👉 Teaching note: Not very common; teach as “dare to” first.

---

---

🟦 3. Semi-Modals

🔹 HAVE TO

• External obligation:

  • I have to finish this report.

• Past form:

  • I had to leave early.

👉 Teaching note: Contrast with “must.”

---

🔹 BE ABLE TO

• Ability (replaces can in other tenses):

  • I was able to solve the problem.
  • I will be able to visit you next week.

👉 Teaching note: Teach as “all-purpose” replacement for can outside present/past simple.

---

🔹 BE SUPPOSED TO

• Expectation/duty:

  • We are supposed to start at 9.

• Common in spoken English for rules or “what’s expected.”

---

🔹 USED TO

• Past habits/states (no longer true):

  • I used to play football every weekend.

👉 Teaching note: Different from “be used to (doing).” Watch out for confusion.

---

🔹 NEED TO

• Similar to have to but softer:

  • You need to study more.

---

🔹 HAD BETTER

• Strong advice/threat:

  • You had better take an umbrella.
  • You had better not be late.