Modal auxiliary verbs

📄️ Introduction

What are modal auxiliary verbs?

📄️ Modals: grammar, pronunciation and contractions

Modal verbs differ from ordinary verbs in several ways.

📄️ Deduction (deciding that something is certain): "must", "can’t", etc

Statements: Emily must have a problem.

📄️ Deduction (deciding that something is probable): "should", "ought to", etc

Present or future

📄️ Chances: "may", "might" and "could"

You may be right; We may go climbing.

📄️ "may" and "might" and "could": some special uses

may in wishes and hopes

📄️ Strong obligation: "must", "will"

The following explanations apply particularly to British English. Americans often use have (got) to where British people use must (see here). However, this use of have (got) to is becoming more common in British English under American influence. And note that must is becoming less common in both British and American English.

📄️ Strong obligation: "have (got) to"

Meaning: obligation, certainty

📄️ "have (got) to" and "must"

Where does the obligation come from?

📄️ Weaker obligation: "should" and "ought to"

Use

📄️ Weaker obligation: "had better"

Meaning

📄️ Expectations: "supposed to"

Be supposed + infinitive is used to say what people have to do (or not do) according to the rules or the law, or to say what is (not) expected to happen.