Professor Thring's mechanical coal miner ______. A: has already been seen by the Coal Board B: is his first invention C: looks like a TV camera D: is not yet in production

What is Professor Thring's invention A: A kind of machine which miners ride on. B: A machine to supply fresh air to tunnels. C: A digging machine operated at a distance. D: A form of metal protective clothing.

What particular advantage does Professor Thring's coal miner have A: It does not have to go deep underground. B: It can work in very narrow spaces. C: It can work in the open air. D: It is twice as strong as a human miner.