Grammar
Coordinating conjunctions: join equal ideas
The train was delayed, so I called my manager. So joins two complete ideas and shows the result. A different conjunction would change the relationship between them.
Use coordinating conjunctions to join equal words, phrases, and independent clauses with a clear relationship.
Read and practice
Read the examples and try the written questions in this guide. Listening recordings are not available for this lesson yet.
Try the written questions
The train was delayed, so I called my manager. /ðə treɪn wəz dɪˈleɪd səʊ aɪ kɔːld maɪ ˈmænɪdʒə/
The short answer
Use a coordinating conjunction to join equal ideas. Choose and for addition, but or yet for contrast, or for a choice, and so for a result.
The train was delayed, so I called my manager.
Why it works: So connects the delay with its result, the call.
5 more examples
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We booked the room and paid online.
And adds a second action by the same subject.
Not this:We booked the room,
but we did not payonline. What changes: But shows that the second clause contrasts with the first. -
The room was small, but it was clean.
But connects two complete clauses with a contrast.
Not this:The room was small,
and it was clean. What changes: And adds information without emphasizing a contrast. -
Would you prefer tea or coffee?
Or presents two alternatives of the same kind.
Not this:Would you prefer
tea and coffee? What changes: And suggests that both drinks are included rather than one choice. -
The shop was closed, so we went home.
So introduces the result of the first clause.
Not this:The shop was closed,
but we waited outside. What changes: But gives a response that contrasts with what the closure might lead you to expect. -
The plan was difficult, yet everyone agreed.
Yet is similar to but and highlights a surprising contrast.
Not this:The plan was difficult,
so everyone asked questions. What changes: So changes the second clause into a result.
Read the full guide
First decide how the two ideas are connected. Are you adding information, showing a contrast, offering a choice, or giving a result? Then choose the conjunction that names that relationship. When both sides are complete clauses, put a comma before the conjunction.
Choose the relationship before the word
A coordinating conjunction does more than hold a sentence together. It tells the reader whether the next idea adds information, contrasts with the first, offers an alternative, or gives a result.
We booked the room and paid online.
And adds one action to another action.
The shop was closed, so we went home.
So shows that going home happened because the shop was closed.
Which conjunction is likely to introduce a result: but or so?
Use so when the second idea is the result of the first.
Use and to add equal items or actions
Use and when two parts belong together as added information. The parts can be nouns, adjective phrases, verbs, or complete clauses.
I packed a jacket and an umbrella.
And joins two nouns that are both things in the bag.
The museum opened late, and the visitors waited outside.
Each side has its own subject and verb, so both sides are complete clauses.
Do not use a comma for a simple pair such as a jacket and an umbrella.
Use but and yet for contrast
Use but when the second idea differs from, limits, or surprises the first idea. Yet has a similar meaning and often makes the contrast feel stronger.
The room was small, but it was clean.
But joins two complete clauses that give contrasting information.
The plan was difficult, yet everyone agreed.
Yet signals that agreement is surprising after the description difficult.
Choose the clearer link: The weather was cold, ___ we went swimming.
Use but or yet. Going swimming contrasts with the cold weather.
Use or to offer an alternative
Use or when the listener can choose between alternatives. It can join single words, phrases, or complete clauses.
Would you prefer tea or coffee?
Or links two drink choices of the same grammatical type.
You can email me, or you can leave a message.
Each side has a subject and verb, so the comma helps separate the two complete clauses.
Use and when both items are included. Use or when one alternative is expected.
Use so to show a result
Use so when the second clause happens as a result of the first. The first clause gives the cause, and the second clause gives the consequence.
The shop was closed, so we went home.
The closure is the cause and going home is the result.
I missed the last bus, so I took a taxi.
Taking a taxi follows from missing the bus.
Which conjunction completes the sentence: The printer had no paper, ___ I used another one?
Use so because using another printer is the result of the first problem.
Use commas with two complete clauses
Put a comma before and, but, or, so, or yet when the conjunction joins two independent clauses. An independent clause has its own subject and verb and can stand as a sentence.
The museum opened late, and the visitors waited outside.
The museum opened late and the visitors waited outside are both complete clauses.
I packed a jacket and an umbrella.
A jacket and an umbrella are only two nouns, so no comma is needed.
Read each side of the conjunction on its own. If both sides can stand alone, use the comma in standard edited writing.
Before you go
Remember this
Join equal ideas with a conjunction that shows their relationship. Use and for addition, but or yet for contrast, or for alternatives, and so for a result. Put a comma before the conjunction when it joins two complete clauses, but leave out the comma when it only joins words or phrases.
Practice with the written examples
You can practice with the written questions in the Learn tab. Each answer includes an explanation.
Try the written questionsListening test not available yet
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Try the written questionsQuestions about "Coordinating conjunctions: join equal ideas"
What are coordinating conjunctions?
Coordinating conjunctions join words, phrases, or clauses that have equal grammatical weight. The common set is and, but, or, so, yet, for, and nor. The conjunction tells the reader whether the ideas add, contrast, offer a choice, or show a result.
We booked the room and paid online.
When should I use and, but, or, and so?
Use and to add information, but to show a contrast, or to offer an alternative, and so to introduce a result. The relationship between the two ideas should guide your choice. Read both sides of the sentence before choosing the conjunction.
We booked the room, but we did not pay online.
Do I need a comma before a coordinating conjunction?
Use a comma before and, but, or, so, or yet when the conjunction joins two independent clauses. Each clause must have its own subject and verb. Do not normally use a comma when the conjunction joins only words or short phrases.
The room was small, but it was clean.
What is the difference between but and yet?
Both but and yet show contrast. Yet often gives the contrast a slightly more surprising or formal feeling. In everyday writing, but is usually the more common choice. Choose the one that gives the relationship between the ideas the right strength.
The room was small, and it was clean.
How do I use for and nor?
For can introduce a reason, mainly in formal writing. Nor can continue a negative idea, often after neither or another negative clause. These conjunctions are less common in conversation, so use them when the sentence structure and level of formality make them suitable.
Would you prefer tea or coffee?