Positive and negative agreements /əˈɡriːmənts/
1. Positive agreement. You should use this form after affirmative statements.They can be formed with SO or too and a positive form of the auxilary verb:
- I like coffee. - So do I./ I do too
- I have seen this film. - So has he. / He has too
- Nick can sing well.- So can Ann./ Ann can too
2. Negative agreement should be used after negative statements and can be formed with the words either or neither: either is used after a negative form of the auxilary verb and neither is used before a positive one.
- He wasn't late yesterday. - Neither was I./ I wasn't either .
- Eugene can't play chess. - Neither can Sam./ Sam can't either.
neither can be pronounced in two ways : /ˈnaɪðə(r)/ or /ˈniːðə(r)/
see the related video
check yourself here: