Gerunds and Infinitives

Here is a brief review of the differences between gerunds and infinitives.

Gerunds are formed with ING.

walking, talking, thinking, listening

Infinitives are formed with TO.

to walk, to talk, to think, to listen

Both gerunds and infinitives can be the subject of a sentence.

Writing in English is difficult.
To write in English is difficult.

Both gerunds and infinitives can be the object of a verb.

I like writing in English.
I like to write in English.

But... only gerunds can be the object of a preposition.

We are talking about writing in English.

It is often difficult to know when to use a gerund and when to use an infinitive. These guidelines may help you.

Gerunds	Gerunds are often used when actions are real, concrete, or completed. For example: I stopped smoking. (The smoking was real and happened until I stopped.)
Infinitives	Infinitives are often used when actions are unreal, abstract, or future. For example: I stopped to smoke. (I was doing something else, and I stopped; the smoking had not happened yet.)

GRAMMAR VI