Can I put "enough" at the end of this sentence? Or is it a rule to put "enough" before -ing?
Great question. Technically this is a rule. Peppa's mom is saying that the vegetables don't need to be washed more. They have had the necessary amount. In order to convey that meaning, "enough" has to come before the "ing" form. Ex: That's enough talking. (Meaning we have talked the necessary amount). Ex: That's enough cooking. I don't think we need any more food.