Understanding Modal Verbs: Must and Should

This video tutorial explains the differences between 'must' and 'have to' in terms of obligation and probability. It covers their usage in present, past, and future tenses, highlighting key exceptions and common mistakes. The tutorial also introduces 'should' for giving advice and correcting common errors. A free PDF worksheet is available for further practice.

What is the main difference between 'must' and 'have to' when discussing obligation?

• 'Must' is used for hypothetical situations, 'have to' for real situations.

• 'Must' is used for past obligations, 'have to' for future obligations.

• 'Must' is used for rules, 'have to' for necessities.

• 'Must' is used for personal obligations, 'have to' for external obligations.

How do you form the negative of 'must' to indicate prohibition?

• Don't must

• Mustn't

• Not must

• Must not

What does 'don't have to' imply in terms of necessity?

• It is forbidden.

• It is mandatory.

• It is not necessary, but optional.

• It is recommended.

Why can't 'must' be used in the past tense?

• Because it is only used for future obligations.

• Because it only exists in the present simple tense.

• Because it is a modal verb.

• Because it is used for hypothetical situations.

What is a common mistake students make when using 'must'?

• Using 'must' for hypothetical situations.

• Using 'must' for recommendations.

• Using 'must' in the past tense.

• Using 'must' with a preposition 'to'.

How is 'must' used to express probability in the present tense?

• To indicate something is optional.

• To indicate something is mandatory.

• To indicate something is very likely.

• To indicate something is impossible.

What does 'have to' imply when used for probability?

• It indicates no probability.

• It indicates the same probability as 'must'.

• It indicates a higher probability than 'must'.

• It indicates a lower probability than 'must'.

How do you express probability in the past using 'must'?

• Must be + past participle

• Must + past participle

• Must have + past participle

• Must had + past participle

What is the correct structure for using 'should' in the past tense?

• Should + verb

• Should have + past participle

• Should be + verb

• Should had + past participle

What is a common mistake when using 'should'?

• Using 'should' with a preposition 'to'.

• Using 'should' for future recommendations.

• Using 'should' for past obligations.

• Pronouncing the 'l' in 'should'.