求英文中，不但....而且，既....又等关联词用法

not only A but also B 谓语动词看B
not only 放句首 句子部分倒装

not only ...but also
This stuff is not only good but (also) inexpensive.
Not only did they go, but they had great fun.

"also" is often dropped colloquially.
When "not only" appears in the beginning of the sentence, the verb needs to be placed in front of the subject.

both...and...
This stuff is both good and inexpensive.
But, you can't say "They both went and had great fun".(It would mean that both of them went and both had great fun)

Therefore, the stative verbs or nouns connected by "both" "and" are equal (quality wise). But those being connected by "not only" "but also" are not. Usually the emphasis is on the "but also" side.

not only...but also...