Semi-Modals (be about to, be supposed to, be bound to)

1. Overview & Concept

• What is it? Semi-modals (also called marginal modals or quasi-modals) are verb phrases that function like modal verbs but are formed with be or have + another element. They express meanings similar to core modals but add nuance around timing, expectation, certainty, and social obligation.
• Purpose: To add precision to modal meaning — particularly for near-future events, expectations, social duty, and certainty about outcomes.
• Why C1? They require control of aspect, tense agreement, and often carry register sensitivity that separates proficient users from intermediate ones.

2. Structure & Formula

3. Usage Rules

• Be about to: Something will happen in the very immediate future (seconds or minutes).
• The film is about to start — sit down.
• I was about to call you when you walked in.

• Note: Does NOT combine with future time words (soon, tomorrow) — it implies imminence.

• Be supposed to: Expectation or arrangement. Often implies the expectation is not being met.

• You're supposed to wear a seatbelt by law.
• He was supposed to arrive at nine, but he's still not here.

• It's supposed to be a great restaurant (= people say it is, I expect it to be).

• Be bound to: Near-certain prediction of an outcome, often based on someone's character or a logical chain.

• She's been studying all year — she's bound to pass.

• If you ignore the problem, it's bound to get worse.

• Be likely to: Strong probability without certainty. More formal than probably will.

• The project is likely to be delayed.

• Interest rates are likely to rise next quarter.

• Had better: Strong advice, especially when there are negative consequences if not followed. More urgent than should.

• You'd better leave now or you'll miss the train.

• I'd better not say anything — it might cause trouble.

• Be due to: Expected according to a schedule or plan.

• The train is due to arrive at 3:15.

• She's due to give birth next month.

• Be meant to: Intended purpose or expectation based on design or social norm.

• This software is meant to save time.
• You're not meant to use your phone in the library.

4. Signal Words & Context

5. Common Pitfalls

6. Real-World Examples

1. Hurry up — the presentation is about to begin.
2. You're supposed to submit the form by Friday.
3. She's been training for months — she's bound to win the race.
4. House prices are likely to rise again next year.
5. You'd better apologise before it's too late.
6. The CEO is due to announce the decision at noon.
7. This button is meant to reset the device.
8. He was about to leave when his phone rang.
9. They're supposed to have read the report — clearly they haven't.
10. You'd better not be late — the client has zero patience.

7. Summary Table