EXPLANATION Infinitive verbs are verbs such as to be, to run, to study, to split. As the word infinitive suggests, these verbs do not indicate tense (time). Some people believe that the two words in the infinitive verb should never be separated, although most people believe that it is okay in some circumstances to insert an adverb between the two words - especially for emphasis.
Perhaps the most famous example of the splitting of an infinitive is in the television series Star Trek. The mission of Star Trek, stated at the beginning of the program, is:
In the Star Trek example, the infinitive verb is to go and the adverb that has split the infinitive is boldly. The mission might have been stated as 'to go boldly where no man has gone before', but maybe that would not have had the same emphasis; the phrase would certainly have lost its rhythm.
There are some sentences where it is difficult to see where else the adverb could go if not within the infinitive. Take, for example, the sentence:
It is impossible to place the compound adverb anywhere else!
Whether or not it is grammatically incorrect to split the infinitive will long be debated. The best approach is to avoid splitting the infinitive unless there is a definite reason for doing so.