若已知某行星绕太阳公转的半径为r，公转的周期为T，万有引力常量为G，则由此可求出（   ）

人类社会发展离不开能源，而开发氢能源是实现社会可持续发展的需要．

（1）目前人类生活、生产中重要的三大化石燃料：煤、石油、天然气：其中天然气主要成分的化学式为 ____；化石燃料燃烧会加剧温室效应．下列符合“低碳生活”理念的做法是 ____（填序号）．

A．提倡用燃煤火力发电

B．推广利用太阳能、风能、缓解温室效应

C．出行多乘坐公交车，少开私家车

（2）氢气是理想的清洁、高能燃料．工业上可用煅烧黄铁矿（主要成分FeS₂）产生的二氧化硫，通过下列工艺过程制取氢气：

①写出膜反应器中HI气体发生分解反应的化学方程式 ____；

②生产流程中可被循环利用的物质是 ____．

阅读理解

B

        Not only adults but also teenagers have problems in their life. Here is a survey showing the main problems of teenagers.

        They feel stressed because they have too much homework to do both at school and at home. They have lots of exams to take. And parents usually send them to different classes at weekends. They don't have their own time to do what they are interested in.

        Now more and more teenagers are getting short-­sighted. They often read in bed or keep reading for a long time without having a rest. Some of them are crazy about playing computer games. Some spend too much time watching TV.

        Another serious problem among teenagers is that many of them are becoming fat. They eat too much junk food, but they take little exercise.

        I think teenagers should think of ways to deal with problems. They should make a plan for study and hobbies and find time to relax as much as possible.

①正确地反映时代的任务和要求

②牢牢地把握时代的脉搏

③正确总结时代的实践经验和认识成果

④反映一定社会和时代的经济和政治