A.量子棘轮具有对电子的制导作用,因此电子不仅可以远离负极也可以自动靠近负极。
B.应用量子棘轮推翻了经典物理学有悖于量子理论的观点,验证电子确实是一种概率波。
C.量子棘轮能吸收电子携带的热量,用它做成的热力泵,最适合给芯片的微元件降温。
D.电子在没有有向电压的环境中能自由运动,也就是说电子没有方向性,可向各处逃逸。
A.借助无有向电压的电子设备可使电子定向分流
B.具有转圈、上下乃至爬波等多种电子运动形式
C.通过特定信号控制电子的流向以完成有用运动
D.将促进物理学、生物化学等学科的研究与发展
1.B 2.D 3.A 4.B
A.分子马达协调运作使其吸收的无方向能量成为定向能量以满足人体需要
B.众多的分子马达协调运作使肌肉产生有效能量以适合人体各部分的需要
C.肌肉在周期力的作用下完成有用的单向运动以抵消体内能量的无方向性
D.肌肉将吸收的无方向化学能量进行改造再释放以补充人体所消耗的能量
1.不能。因为“唯一的”即“独一无二”,准确地说明了要改变这种困难,除找到既环保又可再生的替代性能源外,别无他法。
2.因为氢燃烧后产生的是水,而这种水对自然界完全无污染,所以氢动力汽车可以实现“零污染”。
3.①科技的发展和巨大市场利润的刺激;②石油面临枯竭的威胁,汽车终有一天会无油可有;③氢既环保又可再生;④氢无处不在
4.中心句是:氢能源的开发技术是氢动力汽车最终走进寻常百姓家的关键。
15.下列表述符合原文意思的一项是:(2分
A.世界上最长、最快的高速铁路干线是武汉到广州的高铁客运专线。
B.世界各国都在大力推进铁路的高速化,旨在减少废气排放,节约石油资源。
C.从武汉到广州,如果你坐在“和谐号”列车六号车厢,那么,你就是坐在动车车厢内。
D.为了防止高速列车行进在弯道时造成脱轨事故,在路轨的设计上采取了尽量提高PQ值的技术措施。
16.第⑤至⑨自然段介绍了高速铁路的特别要求,其中⑦至⑨三段各介绍了哪一个方面的要求?(3分
17.第③段中的画线句子运用了哪些说明方法?有什么作用?(3分
18.高速铁路“将改变人们的地理概念和生活方式”。高铁现已修到我们家乡,它将给我们的生活带来哪些新的变化?(至少答出两点(3分
Last Sunday, Jim went out to fly a kite. The kite flew highly in the sky. Jim ran with it happily.
Suddenly the line was broken and the kite flew away. Soon it disappeared. Where was it?
Jim had no idea. So he had to run here and there to look for the kite. At last he saw it on the top of the tree. He tried to get it down. But he couldn’t. He felt sad.
1。 头绪分明,脉络清楚
写好记叙文,首先要头绪分明,脉络清楚,明确文章要求写什么。要对所写的事件或人物进行分析,弄清事件发生、发展一直到结束的整个过程,然后再收集选取素材。这些素材都应该跟上述五个“ W ”和一个“ H ”有关。尽管不是每篇记叙文里都必须包括这些“ W ”和“ H ”,但动笔之前,围绕五个“ W ”和“ H ”进行构思是必不可少的。
2。 突出中心,详略得当
在文章的框架确定后,对支持故事的素材的选取是很关键的。选材要注意取舍,应该从表现文章主题的需要出发,分清主次,定好详略。要突出重点,详写细述那些能表现文章主题的重要情节,略写粗述那么非关键的次要情节。面面俱到反而使情节罗列化,使人不得要领。这一点是写好记叙文要解决的一个基本问题,也需要一定的技巧。如:
One night a man came to our house and told me, "There is a family with eight children。 They have not eaten for days。" I took some food with me and went。
When I finally came to that family, I saw the faces of those little children disfigured (破坏外貌) by hunger。 There was no sorrow or sadness in their faces, just the deep pain of hunger。
I gave the rice to the mother。 She divided the rice in two, and went out, carrying half the rice。 When she came back, I asked her, "Where did you go?" she gave me this simple answer, "To my neighbors — they are hungry also!"
3。 用活语言,准确生动
记叙文要用具体的事件和生动的语言对人、事、物加以叙述。一篇好的记叙文的语言既要准确、生动,又要表现力强,这样才能把人、事描写得具体生动,其可读性才强。试比较下面一篇例文修改的前后效果。
原文:
One day Xiaoqiang was wandering away。 He was soon lost among people and traffic。 He could not find the way back home and started crying。 Just then, two young students who were passing by found him standing alone in front of a shop and crying。 They went up to Xiaoqiang and asked him what had happened。 Xiaoqiang told them how he got lost and where he lived。 The two students decided to take him home。 Mother was pleased to see Xiaoqiang come back safe and sound。 She invited the two students into the house and gave them some money, but they didn't take it。 She served them with tea but they left。
修改后:
The other day, five-year-old Xiaoqiang left home alone and wandered happily in the street。 After some time, he felt hungry so he wanted to go back home。 But he found he was lost among the crowded people and heavy traffic。 When he could not find the way home, he started and crying。 Just then, two young students who were passing by from school found him sanding crying in front of a shop。 They immediately went up to him。
"Little boy, why are you standing here crying?" they asked。
"I want Mom, I go home。" said the boy, still crying。
"Don't worry, we'll send you home。"
And they spent the next two hours looking for the boy's house。 With the help of a policeman, they finally found it。
When the worried mother saw her son come back safe and sound, she was so thankful and she invited the students into her house。 Gratefully, she offered them some money, saying it was a way to express her thanks, but the young students firmly refused it and left without even a cup of tea。
© 2022 xuexicn.net,All Rights Reserved.