too,as well和 also用于肯定句和疑问句,too和as well多用于口语,一般放在句末,而also多用于书面语,一般放在句中与动词连用.either 用于否定句和否定的疑问句,往往放在句末.如：
He went there too.
He didn't go there either.
I like you as well.
I also went there.
also,too,as well与either 的区别
also,as well,too,用于肯定句,also常用于be动词,情态动词,助动词之后,行为动词之前；as well,too用于句末；either用于否定句中,置于句末.
例如,
My father is a teacher.My mother is also a teacher.
=My father is a teacher.My mother is a teacher as well.
=My father is a teacher.My mother is a teacher,too.
我爸爸是一名老师,我妈妈也是.
I can’t speak French..Jenny can’t speak French,either.
我不会说法语,詹妮也不会.
如果 as well as用作连词引出比较从句,其义为“和…一样好”.因此,“He speaks Spanish as well as English．”应译作：“他说西班牙语像说英语一样好”.语意的重点依旧在前部,不在后半部.
请注意 as well as以下的用法：
She called on you as well as I．
不但我来看你,她也拜访了你.
She called on you as well as me．
她不但拜访了我,也拜访了你.
在下列句中,as well as表示“像…一样”的涵义：
She as well as you is an English teacher． either 否定句
too 逗号前 句末 肯定句
also 句中 肯定句
as well 句末 肯定句
她像你一样也是英文教师.补 also用于肯定句句中,用于三人以上的肯定；too用于肯定句句末,用于二人之间的肯定.