too either 用在什么句中?否定句 还是 肯定句 疑问句?

表示“也”时,too常用于肯定句句末,其前面有逗号；either（也不）则常用于否定句句末,其前面有逗号。比较：He is from China。She is from China,too。/He isn't a student。She isn't a student,either。