A、It can fly under 12,000 feet. B、It is small and crowded. C、It is good to the environment but a little bit noisy. D、It is faste

W: Mark,these days we all know that time is money. So why is your company working on a new form of transport which will go from London to New York in 37 hours,when we can already get there in seven?
M: Well,it’s true that people traditionally want to get to their destination as quickly as possible,but I think everyone would agree that there is nothing pleasant about flying in a small, crowded passenger jet. That’s why I’ve developed the Aircruise concept. It aims to carry people to their destination in comfort and style.
W: So what is an Aircruise? Is it a type of plane?
M: No,it’s not. (19) It is proposed that the Aircruise will be a huge kite-shaped airship. (20) It will fly at 12,000 feet, but it would be able to fly at just a few hundred feet above the ground if there was something interesting to see on the ground.
W: It sounds like a sort of luxurious hot air balloon.
M: Well, the plan is that it will be powered, not by hot air, but another type of air, hydrogen. With hydrogen as the fuel , you’d be able to reach speed of around ninety miles per hour. It would be pollution-free, and what’s more, it’d be completely silent!
W: Weren’t they very dangerous?
M: (21) They were rather. But technology has moved on a good deal,and scientists are looking for ways that we can create transport options that are more sustainable and kinder to the environment.
W: So,is it actually going into production?
M: Not yet, (22) but it is certainly gaining a lot of attention.
19. According to the conversation, what is an Aircruise?
20. What does the man say about an Aircruise?
21. How dangerous does the man think an Aircruise is?
22. How does the man feel about the future of this Aircruise concept?