1. Agreement
either
neither so
too

2. I am too.
I’m not either.

3. So am I (= I am too), So have I (= I have too)
‘I'm tired.’ ‘So am I.’ (not ‘So I am.’) - ‘I was late for work today.’ ‘So was John.’ - ‘I work in a bank.’ ‘So do I.’ - ‘We went to the cinema last night.’ ‘Did you? So did we.’   Neither am I (= I'm not either), Neither have I (= I haven't either)  
- ‘I haven't got a key.’ ‘Neither have I.’ (not ‘Neither I have.’) - ‘Ann can't cook.’ ‘Neither can Tom.’ - ‘I won't (= will not) be here tomorrow.’ ‘Neither will I.’ - ‘I never eat meat.’ ‘Neither do I.’   Nor … (= Neither): - ‘I'm not married.’ ‘Nor am I.' (= Neither am I.)’

4. We use too and either at the end of a sentence
We use too and either at the end of a sentence.   We use too after a positive verb  :   - ‘I'm happy.’ ‘I'm happy too.’ - ‘I enjoyed the film.’ ‘I enjoyed it too.’ - Mary is a doctor. Her husband is a doctor too.   We use either after a negative verb  (am not / isn't / can't etc.):   - ‘I'm not happy.’ ‘I'm not happy either.’ (not ‘I'm not happy too.’) - ‘I can't cook.’ ‘I can't either.’ - Bill doesn't watch TV. He doesn't read newspapers either.

5.  So am I
 Neither / Nor am I
 I am too
 I'm not either
 Me too
 Me neither
So…..
Neither…..
…..too
…..either

6. I like chocolate.
I don’t like chocolate.
I do, too.
I don’t like chocolate either.
So do I
Neither do I.
Me too.
Me neither.

7. am/is/are …
was/were …
do/does …
did …
have/has …
can/could…
Will / would …
must …
should
So
Neither

8. can you.
neither do they.
so do you
he won’t either.