also，too这两个词都是副词，又都标明“也是”的意思，但在修辞意味和运用场合上有所不一样。它们的差异如下：

（一）一般说来，also用于比照正式formal的场合，口气比too严厉； too是惯熟familiar的用语，运用规模较广。

（二）also在句中的方位要紧靠动词；too在句中的方位比照活络，有时刺进句中，前后用逗号分隔，有时放在句末。

（三）too只能用在必定句中，不可以用于否定句内。在否定句中，只能用either；also则可以用在否定句中。

下面请看例句：

The Hong Kong Chief Executive also heads the university as Chancellor.

香港行政长官也以大学校监身份领导大学。

Reading books is learning, but application is also learning and the more i

mportant form of learning.

读书是学习，买践也是学习，而且是更重要的学习。

We have not heard such a thing. Also, we have never seen such a scene.

咱们没有听见过这种作业，咱们也历来没有见过这种局势。

请留心，一般说来，also在句中的方位应紧靠动词，但有时为了偏重其意，也可以将它放在句首或句末。

Here, too, the colon must be followed by a dash.

这儿也相同，应当在冒号之后加破折号。

Mary, too, can play the piano.

玛丽也会弹钢琴。

Could you speak Japanese? – Yes, and Spanish too.

您会说日语吗？——会的，还会说西班牙语哩。

Also尽管和too同义，但前者大都用于书面语，后者大都用于口语。例：

The lady washed the children and also gave them dinner.书面语

The lady washed the children and gave them dinner too.口语

在口语中，too还可以用 as well替代。

有时分，also在句中的方位不一样，语句的涵义也会跟着改变。例：

John is also concerned in this matter.（1）

John also is concerned in this matter.（2）

John is concerned in this matter also.（3）

（1）句的涵义是：John is concerned in this matter as well as that one.

（2）句的涵义是：John is concerned in this matter, just as somebody else is.

（3）句的涵义是：This matter is the last of many that have been mentioned.