Question

he decided to take break from the mountains turn to academics using not only but also

Answer 1

He not only decided to take break from mountains but also turn to academics.
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Answer 2

The statement after converting it using the “not only but also” is following - He not only decided to take break from the mountains but also turn to the academics.

The “not only but also” is used to put equal importance to 2 different actions in case of a single sentence.