Too / so do I / either / neither do I

We use too and either at the end of a sentence. 

We use too in a positive sentence. 

We use either in a negative sentence. 

TOO / EITHER

TOO

She likes eating fried chicken and her best friend likes fried chicken too. 

I often go to the movies and she goes to the movies too. 

A: I like coffee without sugar 

B: I like coffee without sugar too. 

I like the concert and she liked it, too. 

I already read books and wrote essays too. 

EITHER

I didn’t report to work today. I didn’t take any calls either. 

His wife is not a lawyer, and his mother is not a lawyer either. 

A: I’m not sad. 

B: I’m not sad either. 

I can’t cook and my wife can’t cook either. 

John didn’t do his homework and didn’t submit the report either. 

So am I = I am, too. . 

So do I = I do, too.

Neither am I = I’m not, either

Neither do I = I don’t either. 

So / Neither + am / is / are + Subject 

So / Neither + was / were + Subject 

So / Neither + do / does   + Subject 

So / Neither + did + Subject 

So / Neither + have / has  + Subject 

So / Neither + can   + Subject 

So / Neither + will  + Subject 

So / Neither + should  + Subject 

For example

A: John is watching TV. 

B: So am I. 

A: John is not watching TV. 

B: Neither am I. 

A: Yoni has finished the project. 

B: So have I. / So has Ben. 

A: Yoni cannot speak Spanish fluently. 

B: Neither can I.

A: Sarah looks so beautiful. 

B: So does Jane. 

A: Sarah looks so beautiful. 

B: Neither does Jane.