1.227 'all', 'both', and 'either'

'All' includes every person or thing of a particular kind.

• You cannot say that all prisoners should be treated the same.

'Both' is used to say something about two people or things of the same kind. The two people or things have usually been mentioned or are obvious from the context. 'Both' is sometimes used to emphasize that two people or things are involved, rather than just one.

• There were excellent performances from both actresses.
• Denis held his cocoa in both hands.

'Either' is also used to talk about two things, but usually indicates that only one of the two is involved. When it is part of the subject of a clause, the verb is in the singular.

• No argument could move either old gentleman from this decision.

Note that 'either' can mean both of two things, especially when it is used with 'end' and 'side'.

• They stood on either side of the bed.