Auxiliary verbs

To avoid repeating the main verbs.

I love pizza , but my husband doesn't

Instead of saying but my husband doesn't LIKE

Use so and neither to say that someone or something is the same.

Structure: so+Aux+subject with a positive verb/ neither(or nor)+auxiliary+subject with a negative verb

I loved his latest film. So did I

I haven't finished the book yet. Neither have I

To respond to a statement and say that you or someone are different.

I don't like shopping online -I do. I buy all my clothes online

To make "reply questions" that often show interest or suprise

I went to the psychic yesterday. Did you?

I'll make dinner tonight. Will you?

To show emphasis in a positive sentence, often when you want to contradict what someone has said.

You didn't lock the door.

I did lock the door. I know I did

To make question tags

You won't forget, will you?

She can speak Italian, can she?