Michael Swan编著的 Practical English Usage P355关于not only用法的说明中，例句就有并列项不对等的情况，说明but also后的结构中的省略是正常现象。是被人们接受的。以下是我对这部分的翻译，例句都是原来的。

Not only…but also是相当正式的一个结构。它可以直接用在所修饰的词或短语之前。例如：

We go there not only in winter, but also in summer.

Not only the bathroom was flooded, but also the rest of the house.

The place was not only cold, but also damp.

Not only也可以用于主语和谓语动词之间，这时通常不用助动词do:

She not only sings like an angel, but also dances divinely.

She not only plays the piano, but also the violin.

强调的时候，not only可以移至句首，这时引起主谓部分倒装。这时，but可以省略，代之以分号：

Not only has she been late three times; she has also done no work.

Not only do they need clothing, but they are also short of water.

非正式语体不太使用这种结构，而更喜欢用其它结构，如：

We don’t only go there in winter. We go in summer too.