The pronoun “both” means “one and the other; two together” and may be used in the following structures:
|both + noun in the plural||Both girls are Spanish.|
|both + the + noun in plural||Both the girls are Spanish.|
|both + of + the + noun in plural||Both of the girls are Spanish.|
|without a noun||Which one do you like? Both.|
|both + of + pronoun||I like both of them.|
“Either” and “neither” also used when referring to two people or things.
“Either” means “one or the other of two people or things; whichever”:
Would you like tea or coffee? Either.
Either of the candidates would be ideal for the job.
“Neither” means “none of the two”.
“Either” and “neither” may appear in structures as:
|either/ neither + noun in singular||There are two good pubs in our town. We can go to either pub.
Neither pub is very expensive.
|either/ neither + of the + noun in plural||There are two good pubs in our town. We can go to either of the pubs.
Neither of the pubs is very expensive.
|either/ neither + of + pronoun||We can go to either of them.
Neither of them is very expensive.
“Either” means the same as “also” and “too”, but used only in negative sentences (at the end):
Tom doesn’t like spaghetti.
I don’t like it either.
The expression “either.. or” means an unavoidable choice or elite division between only two alternatives and is used in affirmative sentences:
We can either go to the cinema or spend the evening at home.
Either you get up at once, or I’ll leave without you.
The expression “neither…nor” means not the one nor the other of two people or things; not either and is used in negative sentences.
Neither Kate nor her husband is slim.
In English is the single negative rule:
He was neither young nor handsome.