correlative conjunctions and parallelism

After both … and, either … or, neither … nor, and not only … but also, use the same form on each side. A noun with a noun: both the notes and the files. An infinitive with an infinitive: not only to write but also to edit. A gerund with a gerund: neither calling nor writing. A finite verb with a finite verb: She neither called nor wrote. Do not mix those forms.