1. Agreeing with an affirmative statement
auxiliary verb So + modal verb + subject to be

2. Agreeing with an affirmative statement
I like pizza
I went to the cinema last night
I can cook really well.
I’m going to travel on my vacation.
So do I.
So did I.
So can I.
So am I.

3. Disagreeing with an affirmative statement
auxiliary verb (negative) Subject + modal verb (negative) to be (negative)

4. Disagreeing with an affirmative statement
I like pizza
I went to the cinema last night
I can cook really well.
I’m going to travel on my vacation.
I don’t.
I didn’t.
I can’t.
I’m not.

5. Agreeing with a negative statement
auxiliary verb Neither + modal verb + subject to be

6. Agreeing with a negative statement
I wouldn’t like to live in Haiti.
I don’t have to travel on business.
I shouldn’t go to bed late.
I haven’t seen Julie lately.
Neither would I.
Neither do I.
Neither should I.
Neither have I.

7. Disagreeing with a negative statement
auxiliary verb (affirmative) Subject + modal verb (affirmative) to be (affirmative)

8. Disagreeing with a negative statement
I wouldn’t like to live in Haiti.
I don’t have to travel on business.
I haven’t seen Julie lately.
I couldn’t understand them.
I would.
I do.
I have.
I could.