make a relevant comment.it should have sense at all.
First of all, I must remark that I've really liked the question. Now as far as the answer goes, I suggest you'll try to think and imagine a few steps forward - something like "What will happen if I add this comment". Is it relevant to the subject, Will it contribute to the discussion. Keep trying and best of luck.
If you are a veteran teacher, you treat the students like you would want your own children to be treated. If you know the student to whom you are remarking to also makes a difference and about what you are replying to. I just try not to be unkind. I tell students you can think anything you just don't always say it. Hope this helps.
Other people asked questions on similar topics, check out the answers they received:
Other people asked questions on various topics, and are still waiting for answer. Would be great if you can take a sec and answer them