Auxiliary verbs (also called helping verbs) combine with a main verb to add grammatical meaning. They help express tense, negation, questions, passive voice, and mood.
Primary auxiliaries:
- be — used for continuous tenses and passive voice
- do — used for questions and negations
- have — used for perfect tenses
Modal auxiliaries express possibility, necessity, permission, or ability:
- can, could, will, would, shall, should, may, might, must
Examples:
- "She is running." — be + present participle (continuous)
- "Do you like coffee?" — do + base verb (question)
- "They have arrived." — have + past participle (perfect)
- "You must go." — modal + base verb (obligation)
Common contractions with auxiliary verbs:
- do + not → don't
- can + not → can't
- will + not → won't
- is + not → isn't