(一)一般说来，also用于比较正式formal)的场合，语气比too庄重; too是惯熟familiar)的用语，使用范围较广。

　　(二)also在句中的位置要紧靠动词; too在句中的位置比较灵活，有时插入句中，前后用逗号分开，有时放在句末。

　　(三)too只能用在肯定句中，不可用于否定句内。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 important form of learning.

　　读书是学习，实践也是学习，而且是更重要的学习。

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

　　我们没有听见过这种事情，我们也从来没有见过这种场面。

　　请注意，一般说来，also在句中的位置应紧靠动词，但有时为了强调其意，也可以将它放在句首或句末。

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

　　这里也一样，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虽然和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代替。

　　有时候，also在句中的位置不同，句子的涵义也会跟着变化。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.