Gerunds and Infinitives

Examples:

• Fencing helps you stay in shape. subject of sentence
• Her favorite hobby is fencing. complement of sentence
• I enjoy fencing. object of sentence

Infinitives

An infinitive is the "to" form of the verb. The infinitive form of "exercise" is "to exercise." You can also use an infinitive as the subject, the complement, or the object of a sentence.

When to use gerund or infinitive

Both gerunds and infinitives can be used as the subject or the complement of a sentence. However, as subjects or complements, gerunds usually sound more like normal, spoken English, whereas infinitives sound more abstract. 90% of the time, you will use a gerund as the subject or complement of a sentence.

As the object of a sentence, it is more difficult to choose between a gerund or an infinitive. In such situations, gerunds and infinitives are not normally interchangeable. Usually, the main verb in the sentence determines whether you use a gerund or an infinitive.