题目内容
【题目】 A little battery puts out a little bit of electricity, so you can use it safely for your experiments. But the electricity that comes through the wires in your house or school is much more powerful. 【1】 .
Inside the walls where you live or study, there are big wires that carry electricity. When you plug in a light or radio or other electrical appliance, you are putting the light or radio in the path way of the electricity. You have heard adults warn, “ 【2】,‘ Now do you know why? If you did, you would become part of the electrical path way.
【3】 The electrical current coming through the wires to the wall plug is so strong that it would hurt a lot if you stuck your finger in the plug. Put your finger in there and it could be you, rather than the light bulb, that becomes part of the electrical path way. And that would hurt!
What if you held a piece of metal, like a fork or knife, and stuck it into the wall plug? Don't do it. Why? It's because metals also conduct electricity. 【4】
Don't touch any electrical appliance when you are wet. Can you think why? It's because water is a good conductor of electricity. When your hands are wet or when your body is in a bathtub full of water, the electricity could flow right through you and give you an awful shock, or even kill you.
Electricity is very useful, but it can be dangerous. 【5】If so, electricity can better serve you, instead of hurting you.
A.Life is precious!
B.So stay away from wires.
C.Be careful, be safe and be smart.
D.And you would get a terrible shock!
E.Don't stick your finger into the wall plug.
F.Therefore, keep in mind some safety rules.
G.Your body is a pretty good conductor of electricity.
【答案】
【1】F
【2】E
【3】G
【4】D
【5】C
【解析】
本文为一篇说明文。文章介绍了电在日常生活中会对人造成危害的几个情况及其原因。
【1】
结合前文A little battery puts out a little bit of electricity, so you can use it safely for your experiments. But the electricity that comes through the wires in your house or school is much more powerful. 一个小电池会放出一点点电,所以你可以安全地使用它来进行实验。但是通过家里或学校里的电线的电可能要强大得多。可知,家里的电路使用需要安全操作。F. Therefore, keep in mind some safety rules. 因此,请记住一些安全规则。符合此处语境。故选F项。
【2】
结合前文When you plug in a light or radio or other electrical appliance, you are putting the light or radio in the path way of the electricity. 当你插上电灯、收音机或其他电器时,就是在把电灯或收音机插在电路上。及后文Now do you know why? If you did, you would become part of the electrical path way. 你知道为什么吗?如果你这样做了,你就会成为电路的一部分。可知,如果插入插座孔,就会成为电路的一部分。E. Don't stick your finger into the wall plug. 别把你的手指伸进墙上的插头。符合此处语境。故选E项。
【3】
结合后文Put your finger in there and it could be you, rather than the light bulb, that becomes part of the electrical path way. 把你的手指放在那里,可能是你,而不是灯泡,成为电路的一部分。G. Your body is a pretty good conductor of electricity. 你的身体是很好的导电体。符合此处描述,身体和灯泡一样都是很好的导电体。故选G项。
【4】
结合前文The electrical current coming through the wires to the wall plug is so strong that it would hurt a lot电流通过电线传到墙上的插头,如果你把手指插在插头上会很疼。及前文It's because metals also conduct electricity. 因为金属也导电。可知,金属和人体一样也会导电,电击会使人感到疼痛。如果将叉子插入插座孔,人也会受到电击。.D. And you would get a terrible shock! 你会受到可怕的电击!故选D项。
【5】
结合后文If so, electricity can better serve you, instead of hurting you. 如果是这样的话,电可以更好地为你服务,而不是伤害你。C. Be careful, be safe and be smart. 小心,安全,聪明。提示安全用电的诀窍。故选C项。
【题目】请认真阅读下列短文,并根据所读内容在文章后表格中的空格里填入一个最恰当的单词。注意:每个空格只填1个单词。请将答案写在答题卡上相应题号的横线上。
Potential energy is the energy, chemical or physical, stored within an object, atom or molecule(分子). Think about a car at the top of a roller-coaster (过山车), pausing just before it slopes into the next turn. A log resting in a fireplace just before it is about to be lit is a treasure house of potential energy. As the log burns, the connections between carbon atoms that make up the wood are being broken down, and the potential energy stored within those connections is being released as heat and light. As a comet approaches a planet or star, it slows, momentarily affected by the larger body’s gravity. The potential energy builds up and then reaches a breaking point as the comet accelerates around the larger body, and is shot out to the other side.
Sports show countless examples every day of potential energy being transformed into kinetic energy. Kinetic energy is the energy of movement. When an archer(弓箭手)draws and holds her arrow, her bow is filled with stored potential energy. When she releases the bowstring, all the potential energy is quickly transformed into kinetic energy, which is transferred to the arrow that takes flight.
The transformation of stored potential energy into kinetic energy can also be made use of to power homes, factories and entire cities. The most notable example is the Hoover Dam. The Hoover Dam is an arch-gravity dam by design. This design name is the first clue as to how exactly the dam makes use of energy. Located in the Black Canyon of the Colorado River, the Hoover Dam formed, and now holds back Lake Mead — the largest reservoir in the United States.
Gravity acts as a force upon Lake Mead. Held at bay by the Hoover Dam, the waters of Lake Mead and the Colorado River gain greater potential energy with each passing moment. The Arizona and Nevada spillways(溢洪道)are two means by which the waters of Lake Mead can escape the dam. As the lake water falls over the walls into a spillway, potential energy is instantly transformed into kinetic energy. The channels through which the water normally escapes every day are the four intake towers. These towers allow the water flow through passageways to the powerhouse and hydroelectric generators. When the water reaches the intake towers and is allowed to flow down through the passageways, all the stored potential energy created by the force of gravity acting upon the water is transformed into kinetic energy, just as when water flows over the wall into a spillway. By taking advantage of the transformed potential energy of Lake Mead, the Hoover Dam provides power to California, Nevada and Arizona.
Moments like these happen all across the physical world, whether on the molecular or universe level.
Main points | Supporting details |
What is potential energy? | Potential energy is the energy existing either in the chemical or physical 【1】, which is stored in an object. When a car is sloping into the next turn from the top of a roller-coaster, it is building up potential energy. When a log is burning, the connections between carbon atoms are being broken down, 【2】 potential energy as light and heat. When a comet approaches a planet or star, the potential energy 【3】 to a breaking point and then the comet is shot out to the other side. |
How is potential energy transformed into kinetic energy? | Potential energy can be transformed into kinetic energy, which is the energy【4】 by movement. When the bowstring is released by an archer, the potential energy stored in the full bow is quickly transferred to the arrow, thus transformed into kinetic energy which sets the arrow 【5】 far away. Hoover Dam is the most notable example of energy transformation. Hoover Dam is 【6】 in the Black Canyon of the Colorado River, holding back Lake Mead. The waters of Lake Mead escape the Dam, falling over the walls into Arizona and Nevada spillways, leading to the 【7】 transformation from potential energy into kinetic energy. The 【8】 of potential energy is from the force of gravity acting upon the water |
What 【9】 is the energy transformation made of? | Homes, factories and cities are efficiently 【10】 thanks to the powerhouses and hydroelectric generators taking advantage of the transformed potential energy. |