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阅读理解 We've used the wind as an energy source for a long time.The Babylonians and Chinese were using wind power to pump water for irrigating crops 4000 years ago, and sailing boats were around long before that.Wind power was used in the Middle Ages, in Europe, to grind (磨碎) corn, which is where the term 'windmill' comes from. We can use the energy in the wind by building a tall tower, with a large propellor on the top.The wind blows the propellor round, which turns a generator to produce electricity. We tend  to build many of these  towers together, to make a 'wind farm' and produce more electricity.The more towers, the more wind, and the larger the propellors, the more electricity we can make.It's only worth building wind farms in places that have strong, steady winds, although boats and caravans (大篷车) increasingly have small wind generators to help keep their batteries charged. The best places for wind farms are in coastal areas, at the tops of rounded hills, open plains and gaps in mountains-places where the wind is strong and reliable.Some are offshore.To be worthwhile, you need an average wind speed of around 25 km/h.Most wind farms in the UK are in Cornwall or Wales.Isolated places such as farms may have their own wind generators.In California, several 'wind farms' supply electricity to homes around Los Angeles. The propellors are large, to obtain energy from the largest possible volume of air.The blades can be angled to cope with varying wind speeds.Some designs use vertical turbines (垂直涡轮机), which don't need to be turned to face the wind.The towers are tall, to get the propellors as high as possible, up to where the wind is stronger.This means that the land beneath can still be used for farming. 1. The first paragraph aims to introduce to us________. A. the function of wind power B. the source of wind power C. the nations using wind power D. the history of using wind power 2. How does a wind power work? A. The generator turns the propeller blades and produce electricity. B. The tall tower helps turn the energy in the air into electricity. C. Warm air rises and makes the propellor move round. D. The propellor blown round by wind turns the generator to produce electricity. 3. The best places for building the wind farm are places where______. A. boats and caravans can often be seen B. isolated farms don't have enough electricity C. there are less human activities D. the wind is strong and reliable 4. We can infer from the passage that________. A. wind farms will not take up too much farming land B. wind farms need no fuel because wind is free C. the blades can be angled to turn to face the wind wherever it comes from D. the higher and larger the towers are, the stronger the wind is 5. What can be a suitable title for the passage? A. Where to build a wind farm B. ABC of the using of wind energy C. How to make best use of wind D. Wind energy is the best energy
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【多选题】tRNA 的二级结构特点是 :
A.
呈三叶草状
B.
能配对的碱基可自身回折形成局部双螺旋
C.
不能配对的碱基形成突环
D.
5- 端被磷酸化, 3- 有 CCA-OH
【简答题】变性蛋白质的主要特征是__丧失,其次是__性质改变和__降低。
【判断题】社会工作模式是小组工作中最早产生的工作模式。( )
A.
正确
B.
错误
【简答题】tRNA的二级结构呈____,碱基配对构成的双螺旋区叫____,不能配对的部分叫做____,tRNA一般由____组成,tRNA的三级结构呈____型。
【多选题】tRNA的二级结构特点是()
A.
呈三叶草状
B.
能配对的碱基可自身回折形成局部双螺旋
C.
不能配对的碱基形成突环
D.
5-端被磷酸化,3-有CCA-OH
E.
由两条多核苷酸链形成
【简答题】变性蛋白质的主要特征是( ) 丧失, 溶解度( ) 。
【单选题】多媒体计算机系统是由( )组成的。
A.
硬件和软件
B.
多媒体硬件系统和多媒体软件系统
C.
网络系统
D.
计算机系统
【简答题】tRNA的二级结构呈(),碱基配对构成的双螺旋区叫(),不能配对的部分叫做(),tRNA一般由()组成,tRNA的三级结构呈()型。
【单选题】在各种常用的小组模式中最早产生的工作模式是
A.
社会目标模式
B.
治疗模式
C.
互动模式
D.
发展模式
E.
心理社会模式
【单选题】关于tRNA的叙述,错误的一项是
A.
二级结构一般为单链
B.
通过自身返折可形成局部双螺旋区
C.
双螺旋区内存在A-T、G-C碱基互补配对
D.
链中不能配对的区形成凸环
E.
二级结构均呈三叶草形
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