Grammar: B1 - ✨ Grammar Essentials: 🧩 Parts of Speech & 🏗️ Sentence Structure - Lesson 9: Conjunctions of Reason & Result (because - review, as, since, so - review)

✨ Lesson 9: Conjunctions of Reason & Result (because, as, since, so)

Good communication is logical. We often need to explain the reason¹ something happens, and the result² of that reason. In English, we use specific conjunctions to show this relationship.

Words for Reasons: 'because', 'as', 'since'

These three words all introduce the reason for an action. 'Because' is the most common. 'As' and 'since' are often used when the reason is already known, and they frequently start the sentence.

The punctuation rule is important:

When the reason clause comes first, you must use a comma ( , ). When it comes second, no comma is needed.

• Because it was very hot, we decided to go swimming.
• We decided to go swimming because it was very hot.

• As I was very tired, I went to bed early.
• Since she knows the history well, she is an excellent tour guide.

Word for Results: 'so'

We have already learned 'so'. It does the opposite job: it introduces the result. Remember to use a comma before 'so' when connecting two complete clauses.

• It was very hot, so we decided to go swimming.

Summary: Reason vs. Result

Look at how we can express the same idea by changing the conjunction and the sentence order.

Structure	Example
Reason, so Result	He studied hard, so he passed the exam.
Result because Reason	He passed the exam because he studied hard.
Because/As/Since Reason, Result	Because/As/Since he studied hard, he passed the exam.

🧠 Practice Quiz: Choose the Best Conjunction

Choose the best conjunction (because, so, as) to complete the sentences.

1. He was hungry, ______ he ordered a big bowl of noodles.
   → so
2. He ordered a big bowl of noodles ______ he was hungry.
   → because
3. ______ it was getting late, we decided to take a tuk-tuk back to our hotel.
   → As / Since
4. I want to visit the Landmine Museum ______ I am interested in Cambodian history.
   → because

📝 Homework: Connect the Ideas

You are given a reason and a result. Connect them into one sentence using 'so', and then again in a second sentence using 'because'.

Reason: The weather was beautiful.
Result: We took a lot of photos.

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Sentence with 'so':
________________________________________________

Sentence with 'because':
________________________________________________

(Answers: The weather was beautiful, so we took a lot of photos. We took a lot of photos because the weather was beautiful.)

Vocabulary Glossary

1. Reason: (Noun) - ហេតុផល (haet phâl) - The cause or explanation for an action or event; it answers "Why?". ↩
2. Result: (Noun) - លទ្ធផល (lôt'thâ phâl) - A consequence or outcome of an action or event. ↩