Question

Locate the gerund or gerund phrase and identify its noun function in the sentence. By preparing, Justin was able to pass the test with flying colors.

Answer 1

A gerund is a verbal used as a noun. It ends in -ing.
ur gerund phrase in this sentence is " by preparing "....and it is functioning as the object of the preposition.

Answer 2

Answer:

By preparing

Explanation:

In the prepositional phrase above ,preparing -in italics- is the gerund.  A preposition is always followed by a noun , so if the idea comes from a verb , this verb has to be nominalised. A verb is nominalised through its gerundial form. By preparing can be substituded by this way // by this means , Justin was able to.... Notice that the gerund has been replaced by a noun phrase, and if we ask: "How was Justin able to pass the exam ...? "; the answer will be: "By preparing...." . Preparing explains the means Justin used; he prepared  himself ,probably hard. All this verbal structure can be nominalised through a gerund. The gerung is functioning as a complement to the preposition.