I think Marilyn has answered the question, but I'll clear up some other things.A gerund is, indeed, a verb used as a noun, but it must always end in "ing": "I enjoy running." An infinitive is also a verb form used as a noun and is usually, but not always, preceded by the word "to": "To run or walk, that is the question." In the latter case, walk is an infinitive without the "to". A participle is also a verb form used as an adjective: "Run down by a DUI, she was seriously injured."
The participle is often used incorrectly and "dangled": "Run down by a DUI, an ambulance took her to the hospital." As a group, verbs that are used as nouns are called verbals.
And that's the end of that lesson.
