[解析]
(1)词句猜测题。根据划线词上文More than 90% of transport fuel is petrol based,but if more vehicles used hydrogen(超过90%的交通燃料是以汽油为基础的,但如果更多的车辆使用氢)可知,如果使用氢气的话温室气体排放量会"下降"。由此可知,划线词的意思是"下降"。A.Stop.停止;B.Decrease.下降;C.Continue.继续;D.Disappear.消失。故选B项。
(2)段落大意题。根据第三段中的However,hydrogen is not considered an ideal replacement for gasoline as an engine fuel for cars because it is harder to store safely.(然而,氢并不被认为是汽油作为汽车发动机燃料的理想替代品,因为氢更难安全储存)和Also,finding investment for storage,pipelines and fuel stations is still a challenge for many nations.(此外,为储存、管道和燃料站寻找投资对许多国家来说仍然是一个挑战)可知,本段主要讲了使用氢作为汽车燃料的挑战。故选C项。
(3)细节理解题。根据第五段中的Thankfully,research is advancing all the time.Nanoscale (纳米级的) thin films are applied to improving the chemical process to rapidly harvest hydrogen from the seawater.(值得庆幸的是,研究一直在进步。纳米薄膜被应用于改善化学过程,以快速从海水中获取氢气)可知,采用纳米级薄膜技术使得从海洋中获取氢气更有效。故选D项。
(4)标题归纳题。根据第一段中的Introducing electric vehicles (EV) and declining gasoline use are helping,but zero﹣carbon hydrogen can speed up both the transition (转变) and long﹣term decarbonization of transport.(引入电动汽车(EV)和减少汽油使用是有帮助的,但零碳氢可以加快交通的转型和长期脱碳)及下文内容可知,文章主要介绍了清洁能源氢气的开发和利用情况。由此可知,选项A"清洁能源氢准备起飞"适合用作文章标题。故选A项。