Modals

Can, can't, must, have to for ability and obligation

Introduction

Modal verbs are special auxiliary verbs that express ability, possibility, permission, and obligation. They don't change form for different subjects and are always followed by the base verb.

At the basic level, "can" and "must" are your essential modals. "Can" expresses what you're able to do or what's possible. "Must" and "have to" express what you need to do.

These modals add nuance to your sentences, moving beyond simple statements of fact to express what's possible, permitted, or required.

Themes

All Grammar (Basic) in This Chapter (13)

• can / can't Expresses ability, possibility, or permission
• must / have to Expresses obligation or necessity
• could (past ability) Expresses past ability or past possibility
• may / might Expresses possibility or asks for permission
• will (future) Expresses future actions, promises, and spontaneous decisions
• going to (future) Expresses planned future actions and predictions based on evidence
• Let's (suggestions) Making suggestions that include yourself
• Shall (offers & suggestions) Offering to do something or making suggestions
• should / shouldn't (Basic Advice) Giving simple advice or opinions
• could (Polite Request) Making polite requests and asking for permission
• would like Polite way to express wants
• May I...? (Formal Permission) Asking for permission formally
• might (Weak Possibility) Expressing something is possible but uncertain