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  • Jake Magnum

Do I Need to Use a Comma Before "As"?

Updated: Jul 5, 2021



In many sentences, if there is no comma before as, then as means “in the way that” or “while.” When you insert a comma before as, its meaning changes to “because.”

Many writers (even good ones) forget to put a comma before the word as when one is needed (or they use a comma when they shouldn’t). Writers tend to make this mistake when forming sentences in which as separates two independent clauses.


Below is an example of such a sentence. The comma is omitted in the first example and is included in the second.


George cleaned the house as his wife had asked him to.

George cleaned the house, as his wife had asked him to.


Both of these examples are grammatical. However, they do not mean the same thing, and so it is important to know how the use of a comma changes the meaning of the sentence.


Adding the comma did not change the meaning of any words in the sentence except for one: as. In sentences with the structure of our example, if there is no comma before as, then as means “in the way that” or “while.” When you insert a comma before as, its meaning changes to “because.”


So, the first sentence above, which contains no comma, can be rephrased as “George cleaned the house in the way that his wife had asked him to.”


The second sentence, which contains a comma, can be rephrased as “George cleaned the house because his wife had asked him to.”

Note that, for certain sentences, there is only one correct decision regarding the use of a comma based on the context.


George cleaned the house as he listened to the radio.

George cleaned the house, as he listened to the radio.


Putting a comma before as in this sentence is a mistake. George clearly cleaned the house while he listened to the radio, not because he was listening to the radio. The second sentence is still grammatical, but it isn’t logical.

댓글 17개


게스트
2023년 10월 09일

What about "as opposed to?" How do commas work with that phrase?

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게스트
2022년 12월 07일

This is nonsense. You don't use a comma before subordinating conjunctions like "because" (look it up) so why would you use one when "as" functions as "because" in a sentence?

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게스트
2023년 6월 05일
답글 상대:

There are exceptions to all rules, especially when it comes to the English language, e.g., where and when you can use the same word. When I read your first example without the comma, it comes across as if she’s going to the store *while* currently needing bread, not *because* she needs it (which is exactly why this article advises to include the comma).

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게스트
2022년 9월 15일

"Lights, shelves, lanterns" as mentioned in lines 52 and 56 of this contract do not add value to the home.


Do I need a comma after contract?

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게스트
2023년 10월 09일
답글 상대:

I think the sentence works best if you have a comma after contract and after lanterns.

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게스트
2022년 6월 12일

Is it correct to say "The book was exceptionally well edited as I encountered no errors while reading."?

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게스트
2022년 11월 27일
답글 상대:

Clearly the as means because so comma is needed.

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게스트
2022년 6월 08일

You guys are very helpful, thank you!

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