It is easy to identify whether a finite verb is an infinitive, gerund or participle. Infinitives usually have the marker to. Examples are: to sing, to work, to break, to stop etc.

Present participles and gerunds are both ing forms; however, they are used in different ways. Gerunds are verbal nouns. That means they serve the same purpose as a noun. When an ing form is used as the subject or object of a verb or the object of a preposition, it is a gerund. Study the examples given below.

• Singing is his hobby. (Here the ing form singing is the subject of the verb is; hence it is a gerund).
• I enjoy swimming. (Here the ing form swimming is the object of the verb enjoy; hence it is a gerund.)
• I am not used to working hard. (Here the ing form working is the object of the preposition to; hence it is a gerund)

Present participles are used to form continuous tense forms. They are also used to connect two clauses.

Note that when a present participle is used to form a continuous tense form, it is not a non-finite verb.

For example, the present participles used in the following sentences are not non-finites.

• I am writing.
• They are waiting for us.
• It is raining heavily.
• They have been working on that project for six months.

When present participles are used to connect two clauses, they are non-finites.

• Smiling beautifully, she greeted all guests. (She smiled beautifully. She greeted all guests)

Here smiling is a non-finite and it is a present participle.

• Standing on tip-toe, he reached for the mango. (He stood on tip-toe. He reached for the mango.)

Here the ing form standing is a present participle.

The past participle is the third form of the verb. When it is used to make perfect tenses or passive verb forms, it is not a non-finite verb.

When it is used to connect two clauses, it is a non-finite.

• Deceived by all his friends, he gave up his pursuit. (He was deceived by all his friends. He gave up his pursuit.)

Here the past participle deceived is a non-finite verb.