分两种情况：
1.若either表示“也（不）”,用于否定句,只能放在句末.如：He doesn't like milk.I don't like it,either.
2.若either表示“两者中的任何一个”,就放在句中,而不能放在句末.
如：There are many shops on either side of the street.
She can either sing or dance.