1. not only … but also 应连接两个相对称的并列成分。例如：
Not only Mr Lin but also his son joined the Party two years ago. （连接两个主语）
I not only play tennis but also practise shooting. （连接两个谓语动词）
He plays not only the piano but also the violin. （连接两个宾语）
They speak English not only in class but also in the dormitory. （连接两个地点状语）
注 1 ： She not only sings well but also dances beautifully.
= She doesn't only sing well but also dances beautifully.
注 2 ：句子 He not only plays the piano but also the violin 不是好的文体，因为 but also 之后的成分与 not only 之后的成分不对称。
