Hmm. I learned a few things while researching today's grammar post. I honestly thought I knew how to properly use the words: not only, but also. Now ... well ... I am smarter than I was yesterday.
First, from Strunk & White:
"Correlative expressions (both, and; not, but; not only, but also; either, or; first, second, third; and the like) should be followed by the same grammatical construction" (THE ELEMENTS OF STYLE, p.27).
For example:
Wrong: A day not only for sorrow but also joy.
Right: A day not only for sorrow but also for joy.
Second, from The Grammar Girl:
When not only is followed by but also ... it's considered good form to make sure the parts that follow each set of words are formatted the same way.
He is not only a great swimmer, but also a great musician. (Good: the sentence uses two noun clauses, which are underlined.)
He is not only a great swimmer, but also plays amazing music. (Bad: the sentence uses a noun clause and a verb clause. It's bad because they don't match.)
You could make the second example better by rewriting it with two verb clauses:
He not only swims with ease, but also plays amazing music.
Third, from Grammarly Handbook:
Not only… but also can be a difficult correlative conjunction to work with because of the extra words and their placement in the sentence. Just remember to use two verbs that make chronological sense, two adjectives, or two nouns.[wrong] He’s not only funny, but also he’s intelligent.
When using a correlative conjunction, both clauses have to be parallel.
[right] He's not only funny but also intelligent.
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[wrong] Not only is Matthew going to Egypt for a month, but also Greece for a couple of weeks.
Because the subject is after not only, there also needs to be a subject after but also.
[right] Not only is Matthew going to Egypt for a month, but he’s also going to Greece for a couple of weeks.
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Go ahead. Give it a try. Write your best "not only, but also" sentence in the comments! :)