main clause + because + reason clauseUse this order when the result comes first and the reason follows.
Reason Clauses
A2Use because, since, and as to give a reason. Put a full clause after them; if the reason comes first, add a comma before the main clause.
What you'll learn
- Use because to answer why something happens.
- Use since and as for background reasons.
- Build a full reason clause with a subject and a verb.
- Put the reason clause first or second and punctuate it correctly.
- Choose the best reason connector for the sentence.
Structure
Because/Since/As + reason clause, + main clauseWhen the reason clause comes first, separate it from the main clause with a comma.
because/since/as + subject + verbAfter the connector, use a full clause, not only a noun, pronoun, or adjective.
Build a sentence
Connector
Reason
The picnic ended earlybecause it rained
The picnic ended early because it rained.
Use because for a direct reason.
When to use
Answering why
Use because when someone asks why. Why did Lisa leave early? Because she felt sick.
Background reason
Use since or as when the reason is already known or not the main new information. Since the store was closed, Tom went home.
Reason first
Put the reason first to lead into the result. Because Anna was tired, she went to bed early.
Markers
becausesinceaswhyreason
In contrast
vs purpose-clauses
Reason clauses explain why something happens. Purpose clauses explain what someone wants to achieve.
vs two-word-prepositions
Because takes a full clause: because Anna was late. Because of takes a noun phrase: because of the traffic.
Common mistakes
Wrong
Anna stayed home because the rain.
Correct
Anna stayed home because it was raining.
Because must be followed by a full clause with a subject and a verb.
Wrong
We left early because tired.
Correct
We left early because we were tired.
After the connector, the reason needs a complete clause.
Wrong
Tom stayed inside because of it was cold.
Correct
Tom stayed inside because it was cold.
Because goes with a clause. Because of goes with a noun phrase, not with subject + verb.
Wrong
Because Tom was sick he stayed home.
Correct
Because Tom was sick, he stayed home.
A reason clause at the start is followed by a comma.
Wrong
We canceled the picnic because since it was raining.
Correct
We canceled the picnic because it was raining.
Use one reason connector, not two together.
Common misconceptions
❝ Because is the only connector for reasons. ❞
Because is the most direct choice, but since and as also introduce reasons, especially background reasons.
❝ A sentence with because always needs a comma. ❞
Use a comma when the reason clause comes first. When the main clause comes first, the comma often drops.
Skills in this rule (6)
USE_BECAUSE_FOR_REASONw5Use because to give the reason for something
Use because before the reason clause when you answer why something happens. The clause after because has a subject and a verb.
USE_SINCE_AS_FOR_REASONw3Use since and as to give background reasons
Use since or as when the reason is already clear or less important than the main result. Put a full clause after them.
BUILD_REASON_CLAUSE_WITH_SUBJECT_VERBw5Build a reason clause with a subject and a verb
After because, since, and as, use a complete clause such as because Tom was late or since we need more time. Do not stop at just a noun or adjective.
PLACE_REASON_CLAUSE_AT_START_OR_ENDw4Place the reason clause before or after the main clause
You can put the reason first or second. If the reason clause comes first, use a comma before the main clause.
CHOOSE_REASON_CONNECTORw4Choose because, since, or as for the sentence
Choose because for a direct answer to why. Choose since or as for a softer background reason.
RECOGNIZE_REASON_PATTERNw3Recognize common reason patterns in a sentence
Words like because, since, and as can introduce the reason for the result in the main clause. Read the sentence by asking why.