Student or Learner
why we shoudn't use comma before "that"in relative clauses?
We only use a punctuation mark when there is good reason to do so. There is no reason to use a comma in a sentence like
'I have a cat that won't chase mice.'
Please note that a better title would have been 'Comma before "that"?'.
Extract from the Posting Guidelines:
'Thread titles should include all or part of the word/phrase being discussed.'