一种气态烷烃和一种气态烯烃组成的混合物共10g，混合气体的密度是相同状况下H₂密度的12.5倍．该混合气体通过装有溴水的试剂瓶时，试剂瓶的质量增加了8.4g．该混合气体可能是（　　）

    As Robert was one day rambling (漫步) about, he happened to cry out, "Ho, ho!" He instantly (立刻) heard coming back from a hill nearby, the same words, "Ho, ho!" In great 1, he said with a loud voice, "Who are you?"  The same words came back, "Who are you?" Robert now cried out 2, "You must be a very foolish boy." "Foolish boy!" came back from the 3 in the same angry way.

    He then went into the bushes (灌木丛) nearby,4 for the boy who, he thought, was mocking (模仿取笑) him. 5, he could find nobody there.

    When he went home, he told his mother that some boy had hidden himself for the 6 of mocking him. "Robert," said his mother, "you are angry with yourself alone. You heard 7 but your own words."

    "Why, mother, 8 can that be?" said Robert.

    "Have you ever heard an echo?" asked his mother.

    "No, what is that?"

    "You know, when you play with your ball, and throw it 9 the side of a house, it bounces (反弹) back to you. If I were outside, by the side of a hill and spoke very loudly, my 10 would be sent back. Then I would hear again the 11 words that I spoke. That, my son, is an echo. When you thought someone was mocking you, it was only 12 own voice bouncing back. If you had spoken kindly, you would have heard a kind 13. Remember this when you are at play with your schoolmates. If any of them are angry, and speak in a loud, angry voice, remember the 14. Then let your words be 15 and kind. Good and kind people will always find themselves among other good and kind people."

漫画中的学生以“光盘”而自豪是因为“光盘行动”（    ）

①继承了勤俭节约的中华民族的传统美德                ②符合低碳、环保的理念

③有利于形成爱惜粮食、珍惜资源的社会风尚        ④减轻了食堂工人的工作负担

阅读理解

    A team of engineers at Harvard University has been inspired by Nature to create the first robotic fly. The mechanical fly has become a platform for a series of new high-tech integrated systems. Designed to do what a fly does naturally, the tiny machine is the size of a fat housefly. Its mini wings allow it to stay in the air and perform controlled flight tasks.

    “It's extremely important for us to think about this as a whole system and not just the sum of a bunch of individual components (元件),” said Robert Wood, the Harvard engineering professor who has been working on the robotic fly project for over a decade. A few years ago, his team got the go-ahead to start piecing together the components. “The added difficulty with a project like this is that actually none of those components are off the shelf and so we have to develop them all on our own,” he said.

    They engineered a series of systems to start and drive the robotic fly. “The seemingly simple system which just moves the wings has a number of interdependencies on the individual components, each of which individually has to perform well, but then has to be matched well to everything it's connected to,” said Wood. The flight device was built into a set of power, computation, sensing and control systems. Wood says the success of the project proves that the flying robot with these tiny components can be built and manufactured.

    While this first robotic flyer is linked to a small, off-board power source, the goal is eventually to equip it with a built-in power source, so that it might someday perform data-gathering work at rescue sites, in farmers' fields or on the battlefield. “Basically it should be able to take off, land and fly around,” he said.

    Wood says the design offers a new way to study flight mechanics and control at insect-scale. Yet, the power, sensing and computation technologies on board could have much broader applications. “You can start thinking about using them to answer open scientific questions, you know, to study biology in ways that would be difficult with the animals, but using these robots instead,” he said. “So there are a lot of technologies and open interesting scientific questions that are really what drives us on a day to day basis.”