Take two sentences: I'm tired. I want to sleep. Both are correct, but
they sound short and disconnected. Add one small word:
I'm tired, so I want to sleep. Now
they belong together. The second sentence explains the first. That small word,
so, is a conjunction.
Conjunctions are linking words. They join two ideas, two words, or two
sentences. The five most useful conjunctions in English are
and, but, or, so, and because. Once you know them, you can
stop writing in short, choppy sentences.
Practise this topic: when you finish reading, try the
interactive
conjunctions exercises at the top
of this page.
What conjunctions do
A conjunction sits between two parts of a sentence. The parts
before and after the conjunction are connected by it.
Idea 1
+
conjunction
+
Idea 2
|
Idea 1
|
Conjunction
|
Idea 2
|
|
I like coffee
|
and
|
I like tea.
|
|
It is sunny
|
but
|
it is cold.
|
|
We can walk
|
or
|
take the bus.
|
|
I'm hungry
|
so
|
I'm making lunch.
|
|
I'm tired
|
because
|
I worked all day.
|
Use and when the second idea adds to the first. Both ideas are
positive, or both are negative.
- I have a brother and a sister.
- She is kind and funny.
- We went to the park and ate ice cream.
-
I don't drink coffee and I don't drink tea.
And also joins two words of the same type: two nouns (cats and dogs), two adjectives (tall and thin), or two verbs (read and write).
But: shows a contrast
Use but when the second idea is different or surprising compared to
the first.
- The film is long but interesting.
- I want to go out, but it's raining.
- Daniel speaks Spanish but not French.
-
She's only ten, but she plays chess very well.
And connects similar ideas. But connects different ones.
It is hot and I am cold sounds wrong. Use
It is hot but I am cold.
Or: shows a choice
Use or when there are two (or more) options. Only one is true, or
only one will happen.
- Would you like tea or coffee?
-
We can eat at home or go to a restaurant.
- Is your name Anna or Anya?
- You can pay in cash or by card.
In negative sentences, or means "not this and not that":
-
I don't like coffee or tea.
(= I don't like coffee. I don't like tea.)
So: shows a result
Use so when the second idea is the result of the
first. The first idea causes the second.
Cause
+
so
+
result
- It was raining, so we stayed at home.
-
The shop was closed, so I went to a different
one.
-
I have a headache, so I'm taking a break.
-
She was tired, so she went to bed early.
Because: gives a reason
Use because to give the reason for something. The
idea after because answers the question "Why?"
Result
+
because
+
reason
-
We stayed at home because it was raining.
- I'm happy because it's my birthday.
- He's late because the traffic is bad.
- I can't come because I'm busy.
Because can also start a sentence. When it does, you need a comma in
the middle.
-
Because it was raining, we stayed at home.
- Because I'm tired, I'm going to bed.
So vs because
This is the most common confusion at A1. Both link a cause and a result, but
they put them in opposite order.
|
What goes before
|
What goes after
|
|
so
|
cause (the why)
|
result (the what happened)
|
|
because
|
result (the what happened)
|
cause (the why)
|
The same situation, two ways:
-
It was cold, so I wore a coat.
(cause → result)
-
I wore a coat because it was cold.
(result → cause)
Punctuation
The comma rules at A1 are simple. You don't always need a comma, but here is
the safe pattern.
Use a comma before but and so when they
join two complete sentences.
I was tired, but I finished the work.
The shop was closed, so I came home.
No comma before and, or, because in short
sentences.
I have a brother and a sister.
I'm happy because it's my birthday.
If because starts a sentence, use a comma after the whole reason:
Because it's my birthday, I'm happy.
Common mistakes
1. Mixing up so and because.
It was raining because we stayed at home. →
It was raining, so we stayed at home.
Or:
We stayed at home because it was raining. The
reason follows because; the result follows so.
2. Using because of when you need because.
I'm late because of I missed the bus. →
I'm late because I missed the bus.
Because is followed by a full sentence (subject + verb).
Because of is followed by a noun: because of the rain.
3. Starting a sentence with And or But in
writing.
I like films. And I like books. →
I like films and I like books.
In informal writing this can be fine, but at A1 keep and and
but in the middle of a sentence.
4. Using or when both things are true.
I have a sister or a brother. →
I have a sister and a brother.
Use or only for choices or alternatives.
5. Forgetting the second part of the sentence.
I'm tired because. →
I'm tired because I worked late.
A conjunction needs an idea on both sides. Because can never end a
sentence.
Frequently asked questions
What are the basic conjunctions in English?
The five basic English conjunctions are
and, but, or, so, and because. They all join two ideas in one
sentence. And adds information, but shows a contrast,
or gives a choice, so shows a result, and
because gives a reason. Together they cover almost every link a
beginner needs.
What is the difference between so and because?
Both link a cause and a result, but in opposite order:
-
So goes between cause and result:
It was cold, so I wore a coat.
-
Because goes between result and cause:
I wore a coat because it was cold.
The two sentences mean the same thing; only the word order is different.
What is the difference between and and but?
Use and when the two ideas go together naturally:
It's hot and sunny. Use but when the second idea is
surprising or different from the first: It's hot but cloudy. If you
can replace the conjunction with "however," you need but, not
and.
Can you start a sentence with because?
Yes. You can say Because it was raining, we stayed at home. When
because starts the sentence, put a comma after the reason. What you
cannot do is leave because alone with no second idea;
I stayed home because. is incomplete in standard English.
Do you need a comma before and and but?
You usually don't need a comma before and in short sentences:
I have a cat and a dog. Use a comma before but and
so when they join two complete sentences:
I was tired, but I finished the work. The comma helps the reader see
the break between the two ideas.
What is the difference between because and because of?
Because is followed by a full sentence with a subject and verb:
I'm late because the bus didn't come. Because of is followed
by a noun or noun phrase: I'm late because of the bus. They give the
same reason, but the grammar around them is different.
Quick summary
- and = adds information (tea and coffee).
- but = shows a contrast (hot but rainy).
- or = gives a choice (tea or coffee?).
-
so = shows a result (cold, so I wore a coat).
-
because = gives a reason (I wore a coat because it was cold).
For a wider look at how to connect ideas in English, read the blog post
English linking words and connectors guide.
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