Now that you know how these two elements can work in similar ways, it’s time to note an important difference in the gerund/infinitive equation:
A gerund can be the object of a preposition; an infinitive cannot.
Both Gerunds and Infinitives can act as the subject of a sentence:
Thinking is something that comes naturally.
To think is something that comes naturally.
You can use a gerund or an infinitive as the object of a verb:
I like fishing.
I like to fish.
Only a gerund can be the object of a preposition. An infinitive cannot:
We are thinking about walking in the woods.
Gerund/Infinitive Usage
At first glance, it may seem difficult to know when to use an infinitive and when to use a gerund. You will find the following guidelines for gerund/infinitive usage helpful.
Gerunds
Gerunds are best for use in sentences about actions that are real or complete, or that have been completed.
• I stopped worrying about the future.
In this example, the worrying was real and it happened until I stopped.
• We really enjoy climbing mountains.
In this example, the climbing is real and it’s something we like to do.
Infinitives
Infinitives are best for use in sentences about actions that are unreal or abstract, or that will occur in the future.
• I’d like you to think about something.
In this example, I’m asking you to think about something, but the thinking hasn’t happened yet.
• Can we take a walk without you stopping to smoke?
In this example, we’re talking about taking a walk and the smoking hasn’t happened yet.