Grammar – Gerunds and Infinitives for Purpose

by Melanie on February 25, 2010

Gerunds and infinitives are a part of English grammar that many English learners find challenging. In this post, I will help you understand when to use a gerund or infinitive to describe the purpose of someone or something.

In English, both gerunds and infinitives can be used to talk about the reason why we use or do something.

Let’s begin with an example. This is a hair dryer:

There are two ways you can talk about the purpose of the hair dryer. Compare these two sentences …

A hair dryer is for drying hair.

I use a hair dryer to dry my hair.

Can you see the difference between the two sentences above?

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Gerunds

A gerund is a verb that acts like a noun. To form a gerund, add –ing to the end of the verb.

To describe the purpose of something, use for + gerund:

What is a hair dryer for?
A hair dryer is for drying hair.

What is this program for?
This computer program is for editing videos.

*Notice that in the above sentences, the thing being described is the subject of the sentence.

More example sentences:

My lips are for kissing!

Be quiet! A library is for studying, not for socializing!

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Infinitives

An infinitive is the to + verb form. To describe the purpose of someone, use an infinitive.

What do you use a hair dryer for?
I use a hair dryer to dry my hair.

Why did you go to the store?
I went to the store to buy some milk.

Why are you going to Toronto?
I‘m going to Toronto to learn English

More example sentences:

I use my lips to kiss!

Be quiet! I come to the library to study, not to socialize!

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Here’s where it gets confusing:
You can still use for + noun to talk about the purpose of someone, but the noun CANNOT be a gerund:

Why did you buy a box of chocolates?
I bought a box of chocolates for my husband.
I bought a box of chocolates to give my husband.
NOT: I bought a box of chocolates for give my husband.
NOT: I bought a box of chocolates for giving my husband.

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I hope this helped you to better understand when to use a gerund or infinitive to talk about purpose!

 


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