Learning English

Infinitives of purpose

 We use infinitives of purpose to explain why we're doing something:

• You're watching this video to get better at speaking English.

We can also use for + somebody to explain that we're doing an action on behalf of someone else:

• We make these videos for you to get better at English.

In more formal English, we can use in order to or so as to to express purpose:

• The government has raised taxes in order to fund the NHS.
• People have taken to the streets so as to protest against the increase in taxes

We can add 'not' to make these negative - so as not to and in order not to:

• He paid the fine in order not to go to prison.
• I've worked really hard all my life so as not to be poor.

We can use the infinitive of purpose after a noun, pronoun or indefinite pronoun to explain what we need it for or, what we intend to do with it:

• I want a house to live in.
• Do you have any more food to cook?
• Do you have anything to eat?