EnglishClub ESL Forums

Hi folks,

My assumptions are, that following sentences are grammatically
correct:
ex 1. There are A and B, both of which shall be new.
ex 2. There is A or B, either of which shall be new.

However, followings are not correct:
ex 3. There are A and B, either of which shall be new.
ex 2. There is A or B, both of which shall be new.

Are theare any grammatical rules like above?
Are my assumptions correct?

Thanks in advance for your help.

Although none of your sentences are natural, they are all structurally possible.
This is essentially an issue of sense/semantics rather than of grammar.