Auxiliary verbs are “helping verbs.” They do not work alone; they help the main verb to change tense, form questions, or make negative sentences.

1. DID (Past Simple)

We use did (or didn’t) for actions that started and finished in the past. We only use it in questions and negative sentences.

• Note: When you use did, the main verb stays in its base form.

• Example (+): I played soccer yesterday.

• Example (-): I didn’t play soccer yesterday.

• Example (?): Did you play soccer yesterday?

2. WAS / WERE (Past Simple of “To Be”)

We use was (I, he, she, it) and were (you, we, they) to describe states, emotions, or locations in the past.

• Crucial rule: Never use did and was/were together in the same clause!

• Example: She was tired. / They were at school.

• Example (-): She wasn’t at home.

• Example (?): Were you happy?

3. WAS / WERE + Verb -ing (Past Continuous)

We use was/were as auxiliary verbs combined with a action verb ending in -ing to talk about actions that were in progress at a specific moment in the past.

• Example: I was watching TV at 8 PM.

• Example: They were studying when it started to rain.

4. HAVE / HAS (Present Perfect)

We use have (I, you, we, they) and has (he, she, it) as auxiliaries combined with a Past Participle verb to talk about life experiences or actions connected to the present.

• Example: I have visited Paris twice.

• Example: She has finished her homework.