A Participle is formed from a verb by adding a suffix which functions as both a verb and adjective in a sentence. Examples include: swimming, laughing, playing.
An Infinitive is a verb which is made up of a word plus a verb.it is easy to identify because it has "to + the verb". Example include: to sing, to read, to write, etc.
A Gerund is a verb which ends with -ing and plays the part of a noun in a sentence. It can function as subject, object, complement, etc of a sentence.
Therefore, the underlined phrase in the first sentence The students carrying boxes is an example of a participle.
The underlined phrase in the second sentence To text in the middle of a movie is an example of an infinitive.
The underlined phrase in the third sentence Skiing down that slope is an example of a gerund.
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