Transport has a lot to answer for when it comes to harming the planet. While cars and trains are mov

45. C    46. A    47. C    48. D    49. C    50. C
【解析】
本文是说明文。为了使航空旅行更环保,出现了电动飞行。文章介绍了电动飞行的特点、优点、面临的挑战、解决措施和前景。
【45题详解】
推理判断题。根据第一段中 If we want big green sky solutions, we need blue sky thinking. Fortunately, there's plenty of that happening right now, particularly the short-haul flights powered by batteries(如果我们想要大的绿色天空解决方案，就需要藍天思维。幸运的是，现在有很多这样的情况发生，尤其是靠电池供电的短途飞行)由此判断出，人们正在努力使航空旅行更加环保。故选C。
【46题详解】
细节理解题。根据第二段Harbour Air is the largest seaplane airline in North America, flying30000 commercial flights in 40 seaplanes each year. Significantly, all Harbour Air routes last less uan30 minutes, making it perfectly fit for electric engines.可知，Harbour Air是北美最大的水上飞机航空公司，每年有40架水上飞机搭载3万次商业航班。值得注意的是，所有港口航线的飞行时间都不到30分钟，这使得它完全适合于电动引擎。也就是说 Harbour Air的飞行航线短使电动飞行成了可能。故选A。
【47题详解】
猜测词义题。根据下文that electric planes are just much more pleasant to fly in. No loud engine noise, no smell of fuel, just environmentally friendly peace and quiet.可知，电动飞机没有发动机的噪音，没有燃油的味道，只有环保的宁静等优点，因此为乘坐电动飞机的乘客提供更愉快的飞行体验。所以added bonus指的是乘客获得的更愉快飞行体验的额外收获。故选C。
【48题详解】
推理判断题。根据倒数第三段 A battery, even a lithium one, only provides 250 watt-hours per kilogram; compare this to liquid fuel, which has a specific energy of 11, 890 watt-hours per kilogram Carrying adequate batteries, however, would make the plane too heavy to get off the ground. In aircraft., where every bit of weight counts, this can' t just be ignored.可知电池不能提供足够的燃料, 而携带足够的电池会使飞机太重而无法起飞。在飞机上，每一点重量都很重要，不能忽视。由此推知平衡电动飞机电池的功率和重量是电动飞机面临的最大挑战。故选D。
【49题详解】
细节理解题。根据倒数第二段The transition(过渡) from gas to electric in the automobile industry has been made easier by hybrids-vehicles powered by both fuel and electricity.可知从燃料飞行到电动飞行过渡过程中，可以使用燃料和电力混合动力技术。故选C。
【50题详解】
推理判断题。根据最后一段It's certainly an exciting time for electric flying. With companies Harbour Air taking the lead, battery-powered planes, especially on short-haul journeys, are set to come a reality in the next few years.可知电动飞行无疑是激动人心的，电动飞行短途旅行将在 未来几年内成为现实。由此判断出作者对电动飞行的前景是乐观的。故选C。