Riddle: What can be heard and caught but never seen?
This riddle can be a bit of a bag for native English speakers. But if your second language is English, you should remember the topic of phrasal verbs. You have to find something that you can hear and catch but not see.
When someone expresses their opinion on a matter, you hear them. And you catch it. In this riddle, the word “catch” here, of course, does not mean grabbing with your hands. It means your ear “catches” it, or hears it. And if you don’t have psychic powers, you can’t see a remark.
Answer: A Remark.