2019年6月英语六级（第2套 · 含听力）选词填空

The dream of personalised flight is still vivid in the minds of many inventors, some developing cycle-powered craft, others __26__ money into jetpacks (喷气飞行背包). However, the flying car has always remained the __27__ symbol of personal transport freedom.
Several companies around the world have produced __28__ that can drive on roads and fly. Airbus has a futuristic modular (组件式的) concept involving a passenger capsule that can be __29__ from the road-going chassis (底盘) and picked up by a helicopter-type machine.
But all these concepts are massively expensive, require safety certification standards for road and air, need __30__ controls, involve complex folding wings and propellers, and have to be flown from air-strips. So they are likely to remain rich people's playthings rather than practical transport solutions for the masses.
"A car that takes off from some London street and lands in another __31__ street is unlikely to happen," says Prof. Gray, a leading aeronautical engineer. "Sky taxis are much more likely." But that won't stop inventors from dreaming up new ways to fly and trying to persuade investors to back their sometimes __32__ schemes.
Civilian aviation is being disrupted, not by the age-old desires for speed, romanticism and __33__, but by the pressing need to respond to a changing climate. New electric engines coupled with artificial intelligence and __34__ systems will contribute to a more efficient, integrated transport system that is less polluting and less noisy. That may sound simple, but as Prof. Gray says, "When I travel somewhere I like this notion that when I finish my journey I feel better than when I started it. That's completely at __35__ with how I feel today." Now that would be progress.