III. Contextual Matching (7%)        A record-breaking commercial-scale hydrogen plane has taken off in the UK. As the plane rosefrom the runway for what was to prove a smooth and __21.__ flight, the team breathed a sigh ofrelief. The six-seater Piper M-Class had been fitted out at a research and development hub atCranfield airport in the UK to run on hydrogen, and on this __22.__ flight in the late summer of2020 everything worked perfectly. With that flight, ZeroAvia, the California-based start-up that haddeveloped the aircraft with partners in Britain and elsewhere, was ready to move to the next stagein the journey towards zero carbon aviation.
        A catchphrase for the transition to a low or zero carbon economy is “electrifyeverything”—that is, create a world in which most human activities, from manufacturing andconstruction to transport and tourism, run on electricity __23.__ from low or zero carbon sourcessuch as wind, solar and perhaps nuclear power. But there is a problem: some sectors look to behard if not impossible to electrify in the near and medium term, and aviation is, perhaps, __24.__among them. At first glance, hydrogen looks to be a good solution to the challenge of flyingwithout wrecking the climate. Whether hydrogen is used to power a fuel cell or directly __25.__for motive power, the only waste product is clean water. Importantly in the context of flight,hydrogen packs a lot of energy per unit of mass—three times more than conventional jet fuel,and more than a hundred times that of lithium-ion batteries.
       For now, one thing remains almost certain: hydrogen is likely to continue to be __26.__ moreexpensive than conventional jet fuel for years or decades to come, limiting its role in greeningaviation—unless the other costs of aviation come to be weighed __27.__. Campaigners argue thatconventionally-fueled aviation must be priced to reflect the cost of the damage it causes to theclimate. This might mean higher ticket prices, but it could also give us aviation that does not costthe Earth.
 (AB) foremost (AC) nonchalant (AD) combusted (AE) substantially (BC) maiden(BD) otherwise (BE) impartially (CD) uneventful (CE) penchant (DE) generated
【題組】21.