http://speakspeak.com/resources/english-grammar-rules/various-grammar-rules/either-neither-both
One of the tricky things about either, neither and both is knowing if they should be followed by singular or plural nouns and verbs.
The table below explains either, neither and both, and the rules for what should follow them.
| Either, neither, both | |
| We use either, neither and both when we are talking about two things. | |
| either = one OR the other | Would you like tea or coffee? ∼ Either; I don't mind. (= 'You can give me tea OR coffee; I have no preference.') |
| neither = not one and not the other | Would you like ham or beef in your sandwich? ∼ Neither; I'm a vegetarian. (= 'I don't want ham and I don't want beef.') |
| both = the first AND the second | I take both milk and sugar in my coffee. (= 'I take sugar. I also take milk.') |
| We use either with a singular noun. We use either of with a plural noun. We use a singular verb with either andeither of. |
either car either of the cars Either day is fine for me. Either of the days is fine for me. |
| We use neither with a singular noun. We use neither of with a plural noun. We use a singular verb with neither andneither of. |
neither house neither of the houses Neither day was suitable. Neither of the days was suitable. |
| We use both with a plural noun. | both houses both of the houses Both (of) my brothers are tall. |
| We use of before the pronouns us, you,them. | both of us, both of you, either of them, neither of them, etc. |
| Between of and a noun we use these, those or my, your, John's, etc., or the. | both of those houses, neither of mybrothers, both of John's sisters, either of the cinemas |