Use a comma before 'and' when it merges two sentences into one. Do not use a comma before 'and' in a list of two. Only use a comma in a list of three or more if your region uses the serial comma.
A Comma before However
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When Should You Use a Comma Before or After But?
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Comma Before And
When to use comma before which?
When to use comma before which?
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Using a Semicolon before And