1. The sign on the bridge said, "Danger! Low bridge."

2. The sign on the bridge said "Danger! Low bridge."
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Which one is correct? Do we have to put a comma after 'said'? Or are both okay?

Yes, 1 is correct.

Both sentences are correct, but they have slightly different punctuation styles. Let me explain:

1. The first sentence uses a comma after the word "said": "The sign on the bridge said, 'Danger! Low bridge.'" This style follows the convention of using a comma before a quotation when it is part of a larger sentence.

2. The second sentence does not use a comma after the word "said": "The sign on the bridge said 'Danger! Low bridge.'" This style is called direct quotation or dialogue punctuation, without a comma. It is typically used when the quote is a direct, standalone statement.

So, whether to use a comma before or after the word "said" depends on the desired punctuation style. Both are acceptable, but they serve different purposes and convey slightly different nuances.