Expressing Purpose (To, In Order To, So As To, So That) — Grammar Rules, Examples and Exercises — English 4th Year Middle School — Algerian Curriculum

Expressing Purpose in English

When we want to explain why someone does something or the purpose of an action, we use specific structures. The most common ways to express purpose are: to, in order to, so as to, and so that.

1. Using “To” + Infinitive

This is the most common way to express purpose.

Structure: Subject + verb + to + base verb

• I study hard to pass the exam.
• She went to the library to borrow a book.
• They saved money to buy a new car.

2. Using “In order to” and “So as to”

These are more formal than “to” and are often used in writing.

Structure: Subject + verb + in order to / so as to + base verb

• He exercises daily in order to stay healthy.
• She spoke slowly so as to be understood.
• We arrived early in order to get good seats.

3. Using “So that” + Subject + Verb

We use “so that” when the subject of the purpose clause is different or for clarity.

Structure: Subject + verb + so that + subject + can/will/could/would + verb

• I left a note so that he would know where I am.
• She speaks loudly so that everyone can hear.
• He studies hard so that he can get a scholarship.

Comparison Table

Structure	Formality	Example
to + verb	Neutral	I called to invite you.
in order to + verb	Formal	He saved money in order to travel.
so as to + verb	Formal	She left early so as to avoid traffic.
so that + clause	Neutral/Formal	They left early so that they could catch the train.

Exercises

Exercise 1: Complete the sentences

1. I go to school ______ (to/in order to) learn new things.
2. She turned on the TV ______ (so that/to) she could watch the news.
3. He practices every day ______ (so as to/in order to) improve his skills.

Exercise 2: Rewrite the sentences using “so that”

1. I came here to help you. → I came here ______
2. She studies hard to pass the exam. → She studies hard ______

Summary

• Use to + verb for simple purpose expressions.
• Use in order to / so as to for more formal writing.
• Use so that + clause when the subject changes or for emphasis.
• All these structures answer the question “Why?”

📍 Related Lessons

• First Conditional (If Clause Type 1) — Grammar Rules and Exercises — English 4th Year
• Giving Advice (Should, Ought to, Had Better) — Modal Verbs — English 4th Year