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Infinitives of Purpose: Why Are You Doing It?

By the end: I can explain the purpose of an action with to + a verb.

Created by Denis M., British English teacher.

I’m studying:

Try the activities, then check your answers.

Start here

Think of a place you go and explain why you go there.

Read each explanation, say your answer aloud, then open the model and try again. You may write your answer if you prefer. Use invented personal details whenever you like.

Useful preparation: Base verbs; simple present and past statements; because from lesson 14.

Playback speed

Choose a play button when you are ready.

Learn 1

Explain the purpose

Use to + base verb to say why you do something: I go to the library to study. The first part names the action. To study gives its purpose. This to is followed by a verb, not an -ing form.

I go to the library to study.

I use this app to practise English.

A short answer can give the purpose

The questionWhy are you going to the library?

The activity is already clear from the question.

The purpose answerTo study for my English class.

To + base verb answers why in this conversation.

The short answer relies on the question for context. In a complete sentence: I’m going to the library to study for my English class.

Learn 2

Lesson scene for I go to the library to study. People and essential props on white. — I go to the library to study.To study gives the purpose of the library visit.

The first verb shows the time

The purpose phrase stays to + base verb when the first action is past or future. I went to the shop to buy bread. I’m going to call Eva to ask a question. Do not change buy to bought inside the purpose phrase.

I went to the shop to buy bread.

I’m going to call Eva to ask a question.

A future plan followed by its purpose

I’m going to call Miato ask about the class time

Going to call gives the planned action. To ask gives its purpose. Keep ask in the base form even though the call is future.

Learn 3

To or because?

To + verb gives a purpose: I go there to study. Because introduces a reason with a person or thing and a verb: I go there because it’s quiet. Both can explain why, but their grammar is different.

I go there to study.

I go there because it’s quiet.

Guided practice

Try each answer first. Check it, or open a model and its explanation.

Try the form

1. Complete: I use this book ___ learn English.

Compare an answer and explanation

to

To + learn gives the purpose.

2. Complete: She went to the café to ___ Eva. Use meet.

Compare an answer and explanation

meet

Keep the base verb in the purpose phrase.

3. Complete: I study here ___ it is quiet.

Compare an answer and explanation

because

Because is followed by the complete idea it is quiet.

4. Complete: He is going to call me to ___ a question. Use ask.

Compare an answer and explanation

ask

Use the base verb after to.

Build or change a sentence

5. Join using to: I went to the shop. I wanted to buy bread.

Compare an answer and explanation

I went to the shop to buy bread.

Use to buy for the purpose.

6. Join using because: I study here. It is quiet.

Compare an answer and explanation

I study here because it is quiet. / I study here because it’s quiet.

Because introduces the reason clause.

7. Correct: I went there to bought food.

Compare an answer and explanation

I went there to buy food.

The purpose verb stays in the base form.

8. Correct: I use this app for practise English.

Compare an answer and explanation

I use this app to practise English.

Use to + practise for this purpose pattern.

Listen to a short conversation

Listen. Then open the words and read aloud. Try one part with a partner, or say both parts on your own.

Open the conversation transcript

A: Why are you going to the library?

B: To study for my English class.

A: Why do you study there?

B: Because it’s quiet.

Listening checks

Read the question, play its recording, then choose an answer. You can open the transcript whenever you need it.

Listening 1

Read the transcript

I went to the shop to buy bread. Then I went home.

Listening 2

Read the transcript

I go to the library to study. I like it because it’s quiet.

Listening 3

Read the transcript

I’m going to call Mia to ask about the class time.

Lesson scene for I went to the shop to buy bread. People and essential props on white. — I went to the shop to buy bread.Went sets the past time; to buy still uses the base verb.

Make it yours

Speak first, compare a model, then say a new version. These tasks are ungraded.

Speaking task 1

Name three everyday actions and their purposes.

Compare a possible response

I go to the library to study. I use my phone to call friends. I go to the shop to buy food.

Success check: Use to + base verb for each purpose.

This is one possible response. Try again with your own details.

Speaking task 2

Describe two finished actions and explain their purpose.

Compare a possible response

I went to the café to meet Eva. I called my teacher to ask a question.

Success check: Put past time in the first verb, not after to.

This is one possible response. Try again with your own details.

Speaking task 3

Explain both your purpose and your reason for choosing a place to study.

Compare a possible response

I go to the library to practise English. I study there because it’s quiet.

Success check: Use to + verb and because + a complete idea.

This is one possible response. Try again with your own details.

Recap

Listen and repeat. I go to the library to study. I went to the shop to buy bread. I go there to study.

I can explain the purpose of an action with to + a verb.

I can use the main pattern.
I can make one sentence of my own.
I know one thing to practise again.

Keep building your grammar