Grammar: B1 - ⚙️ Verbs in Depth: 🎭 Modals & 🌱 Non-Finite Verbs (Introduction) - Lesson 7: Infinitives of Purpose (I study English to get a better job.)

🌱 Lesson 7: Infinitives of Purpose

In English, we often need to explain the reason or purpose¹ of an action. The most common and simple way to answer the question "Why?" is by using an infinitive² of purpose. An infinitive is a type of non-finite verb³, which means it doesn't show a tense.

The Basic Structure: to + verb

To explain why you do something, you can simply add 'to + verb' after the main clause⁴ of your sentence.

Formula: Main Clause + to + verb (infinitive)

This structure directly answers the question "Why?".

• "Why did you go to the market? I went to the market to buy some vegetables."
• "Many tourists come to Battambang to see the famous bat caves."
• "He is studying hard to get a good job in the future."

Formal Alternatives: "in order to" and "so as to"

For more formal⁵ writing or speaking, you can use the phrases "in order to" or "so as to." They have the exact same meaning as the simple "to + infinitive" but sound more academic or official.

• "She exercises regularly in order to stay healthy."
• "He left early so as to avoid the heavy traffic."

Expressing a Negative Purpose

What if you do something to *prevent* another thing from happening? For this negative purpose, we cannot just use "not to". We must use the full phrases "in order not to" or "so as not to".

Correct: "She studied quietly in order not to disturb her roommate."

Correct: "I wrote down the address so as not to forget it."

Incorrect: She studied quietly not to disturb her roommate.

🧠 Practice Quiz: What's the Purpose?

Complete the sentences with the correct infinitive of purpose.

1. I went to the post office _______ a package to my family.
   Answer: to send / to mail
2. He is saving his money _______ a new motorbike.
   Answer: to buy
3. She spoke very quietly _______ wake up the sleeping baby.
   Answer: in order not to / so as not to
4. Why did you turn on the air conditioner? _______ cool down the room.
   Answer: To cool
5. They took a tuk-tuk from their hotel _______ walk in the hot sun.
   Answer: in order not to / so as not to

📝 Homework: Explain Why

Answer these questions or complete the sentences using an infinitive of purpose.

1. Complete this sentence: "I am learning English..."
   (Example: ...to communicate with people from other countries.)
   _________________________________________
2. Complete this sentence: "Yesterday, I went to the riverside..."
   (Example: ...to watch the sunset.)
   _________________________________________
3. Answer the question: "Why do people exercise?"
   (Example: People exercise to stay healthy and strong.)
   _________________________________________

Vocabulary Glossary

1. Purpose: (Noun) - គោលបំណង (koul'bâm'nâng) - The reason for which something is done or created. ↩
2. Infinitive: (Noun) - កិរិយាស័ព្ទដើម (kĕ'rĭ'ya'sâp daem) - The basic form of a verb, with or without 'to' (e.g., to go, go). ↩
3. Non-finite Verb: (Noun Phrase) - កិរិយាស័ព្ទមិនកំណត់ (kĕ'rĭ'ya'sâp mĭn'kâm'nât) - A verb form that does not show a specific tense, person, or number (e.g., infinitives, gerunds). ↩
4. Clause: (Noun) - ឃ្លា (khléa) - A group of words consisting of a subject and a verb. ↩
5. Formal: (Adjective) - ជាផ្លូវការ (chéa phlɨw'kaa) - Used in serious situations or with people you respect; not casual. ↩