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

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Gerunds and infinitives can do several jobs:

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