There’s no reason why you can’t split an infinitive, such as to go, to write, by placing an adverb between to and the rest of the verb (go, write). To boldly go would not sound the same if it were To go boldly.
Having said that, some people split infinitives unnecessarily and the results are awkward.
They planned to quickly make decisions. (clumsy)
They planned to make decisions quickly. (better)
… to rapidly and effectively address the key issues. (clumsy)
… to address the key issues rapidly and effectively. (better)
P.S. An infinitive is the base form of a verb with to (to help, to dance, to eat).
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