题目

要设计一套实验室利用液体和液体加热反应制备气体的装置，现设计了五步操作，正确的程序是( ) ①将蒸馏烧瓶固定在铁架台上 ②将酒精灯放在铁架台上，根据酒精灯确定铁圈高度，固定铁圈，放好石棉网 ③用漏斗向蒸馏烧瓶中加入一种液体反应物，再向分液漏斗中加入另一种液体反应物，并将导气管放入气体收集器中 ④检查装置的气密性(利用对固定装置微热的方法检查气密性) ⑤在蒸馏烧瓶上装好分液漏斗，连接好导气管 A．②①⑤④③  B．④People turn to magic(魔力)chiefly as a form of insurance--that is, they use it along with actions that actually bring results. For example, hunters may use a hunting charm(咒语). But they also use their hunting skills and knowledge of animals. The charm may give hunters the extra confidence they need to hunt even more successfully than they would without it. If they shoot a lot of game(猎物), they credit the charm for their success. Many events happen naturally without magic. Crops grow without it, and sick people get well without it. But if people use magic to bring a good harvest or to cure a patient, they may believe the magic was responsible.  People also tend to forget magic's failures and to be impressed by its surface successes. They may consider magic successful if it appears to work only 10 per cent of the time. Even when magic fails, people often explain the failure without doubting the power of the magic. They may say that the magician made a mistake in reciting the spell or that another magician cast a more powerful spell against the magician. Many anthropologists(人类学家) believe that people have faith in magic because they feel a need to believe in it. People may turn to magic to reduce their fear and uncertainty if they feel they have no control over the outcome of a situation. For example, farmers use knowledge and skill when they plant their fields. But they know that weather, insects, or diseases might ruin the crops. So farmers in some societies may also plant a charm or perform a magic rite to ensure a good harvest. From the passage, we can learn that the writer of the passage may be _______. A. a hunter     B. a farmer     C. a magician    D. an anthropologist Which of the following can best serve as the title of the passage? A. Magic and Hunting.          B. Magic and Farming. C. Why Magic Works?          D. Why People Believe in Magic? The underlined word “spell”(Paragraph 2) most likely means______. A. magic words.    B. magic events.    C. words or expressions     D. magicians.