Modal Verbs and Their Functions

This comprehensive guide explores the various uses and meanings of modal verbs in English grammar. The content covers both present and past forms, along with their specific applications in different contexts.

Definition: Modal verbs are auxiliary verbs that express possibility, permission, ability, obligation, or necessity.

Highlight: Modal verbs can express different levels of certainty, from absolute certainty (must) to possibility (might/may).

Example: "He must be at home" (99% certain) vs. "He might be at home" (less certain)

Key modal verbs and their functions:

CAN/COULD:

• Expresses ability, possibility, and requests
• Used for polite requests and past ability

MUST/HAVE TO:

• Indicates necessity and obligation
• Used for strong beliefs and deductions

MAY/MIGHT:

• Shows possibility and polite requests
• Used for seeking permission

Vocabulary: Modal perfects combine modal verbs with 'have + past participle' to discuss past possibilities (could have done, must have been)

Quote: "Modal verbs of deduction help express varying degrees of certainty about past and present situations."

The guide also covers negative forms (mustn't, can't) and alternatives (be able to, need to), providing a complete overview of modal verb usage in English grammar.