Unit 5.2

The Infinitive of Purpose

Introduction

To-infinitive structure is used to express someone’s purpose (the reason or the aim of an action).

Form

The infinitive of purpose refers to the infinitive structures in which the subject of the main clause and the performer of the action (expressed by the infinitive) are the same.

The structure of infinitive of purpose is the same as to-infinitive that is:
To + verb

There are different structures to express the purpose: to… /in order to… /so as to…

To make the negative form, we add not before to-infinitive.

Example

  • I went outside to help my mom.
  • He called me to invite us to the beach.
  • We moved not to see see him again.
  • I studied hard in order to pass the exam.
  • He got up early in order not to miss the bus. 
  • We decided to become doctors in order to help people.
  • You work hard so as to become economically independent. 
  • We are leaving now so as not to be late.
  • They read a lot so as to learn new things. 

Use

We use the infinitive of purpose to express a person’s aim. It informs about the reason of doing something.

To express this situation, we can use these structures that are similar in meaning:

  • in order to: to seem more formal;
  • so as to: for everyday use;
  • to: a short form of these two forms above.

Summary

The to-infinitive structure is used to express someone’s purpose.

There are different structures to express the purpose: to…, in order to…, so as to…

To make the negative form, we add not before to-infinitive.

For example:
— “I have to find an excuse togo to the cinema with them.” = The subject expresses his or her aim to go to the cinema.
— “I have to find an excuse not togo to the cinema with them.” = The subject expresses his aim not to go to the cinema.

NOTE: We use in order to and so as to before stative verbs like appearhave, know, seemunderstand… and the negative form in order not to if the purpose is to avoid something.

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