In these two sentences:
- I look forward to get.
- I look forward to getting it.
Why is the first sentence incorrect? When do we use to as an infinitive marker?
It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.If this question can be reworded to fit the rules in the help center, please edit the question.
"Look forward to" is a transitive verb phrase, so it wants a noun for its object. Since "get" is not a noun, it sounds wrong. "Getting it" is a noun phrase that satisfies expectations created by the "look forward to" phrase.
The infinitive verb form may sometimes be used as a noun, but the nuance is more of the abstract idea of the verb ("I like to play.") rather than something specific that someone would be looking forward to. Additionally, having the same word repeated (* "I look forward to to play.") does not sound as natural as alternatives ("I look forward to playing.").