Correct this sentence, I’ve told you this before Arnold, no politics at the dinner table.
I have told you this before, Arnold: no politics at the dinner table.
"I have told you this before, Arnold: no politics at the dinner table."
To correct the sentence, you need to make a few changes:
"I've told you this before, Arnold: no politics at the dinner table."
The correction involves adding a comma after "before" and adding a colon after "Arnold" to introduce the speaker's statement.