2019-07-21 How to give reasons using ‘for’ and ‘to’  – Learners’ Questions

This week’s question

When should I use ‘for’ or ‘to’ to express purpose? – Alex from Spain

Answer this

What do we do when we ‘express purpose’? 

Language points

Infinitive of purpose
The infinitive of purpose is formed with ‘to’ + a bare infinitive verb. We add it to the end of a sentence to explain why we are doing something. We can make things more formal by using ‘in order to’ or ‘so as to’.

• I ran to catch the bus.
• The dog lay down to sleep.
• I ran in order to catch the bus.
• The dog lay down so as to sleep.

Using a noun
We can use ‘for’ + a noun to explain why we are doing something too.

• I ran for the bus.
• The dog lay down for a nap.

Explaining the purpose of an object
We can use ‘for’ + a noun or -ing to explain the purpose of an object – either what it does or how it will be used. 

• I have one pair of shoes for work and one pair for doing sports.

Asking about the purpose of an object
To ask about the purpose of an object – or an action – we use the question ‘What…for?’

• What do you have two pairs of shoes for?
• What did you do that for? I was sleeping!

The answer

When we express purpose we say why we do, are doing or did something.