What is the objection to split infinitives?
The split infinitive is a bone of contention in grammatical circles. There are two camps, one called Prescriptive and the other called Descriptive. The former wants people to adhere to traditional rules, the latter wants to describe what people actually do. You can split the difference, in a way. When it makes more sense to split the infinitive, as in “to boldly go where no man has gone before,” do it. When it is not really needed or wanted for flow or emphasis, it is more correct and often more graceful not to split the infinitive, as in “not to split the infinitive” instead of “to not split the infinitive.” In other words, don’t split for trivial reasons; split for good reasons. Other tenses? Well, in English, once you are past the present and simple past, we use “helper” verbs, mostly “have” and its past “had,” followed by the past participle of the main verb. You can split have and had from the participle easily and it is common, but the same principle of ease of flow and clarity a