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1.75亿学生的选择
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1.75亿学生的选择
有关化学的问题,这道题怎么解...,看不懂,可能没学13、在密闭容器里,A与B反应生成C,其反应速率分别用、、表示,已知2=3、3=2,则此反应可表示为A、2A+3B=2C
B、A+3B=2C
C、3A+B=2C
D、A+B=C13、在密闭容器里，A与B反应生成C，其反应速率分别用va、Vb、Vc表示，已知2Vb=3Va、3Vc=2Vb，则此反应可表示为A、2A+3B=2C
B、A+3B=2C
C、3A+B=2C
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1.75亿学生的选择
分析：根据速率之比等于化学计量数之比确定各物质的系数,据此书写方程式．由于2vB=3vA、3vC=2vB,所以vA：vB：vC=2：3：2,即A、B、C对应的化学计量数分别为2、3、2．故反应方程式为2A+3B=2C．故选A．点评：本题考查反应速率规律,难度不大,注意对基础知识的积累掌握和对反应速率规律的理解．
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其他类似问题
反应速率可理解为这个反应化学方程式配平后的各个分子式的系数比Va：Vb：Vc=2：3：2 所以选A、2A+3B=2C
选A，对化学老师无挑战性。
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1.75亿学生的选择
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1.75亿学生的选择
一道数学题,（英语）b,c项有点看不懂&
暗袭雨天588
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1.75亿学生的选择
b是从x值里找一个学生是80分左右的,c是x高的人对y值有影响吗,
x值里没有80分左右的。。。。
在y值中达到80的学生中数出来所有的x值里的学生，意思就是把y得到了80以上的x学生都挑出来
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其他类似问题
如果是数学
我想我能看懂
扫描下载二维码阅读下列短文，从每题所给的A、B、C、D四个选项中，选出最佳选项，并在答题卡上将该项涂黑。Summer RainThe worst days of any summer are the rainy ones. We spend all year looking forward to nice weather and
阅读下列短文，从每题所给的A、B、C、D四个选项中，选出最佳选项，并在答题卡上将该项涂黑。
Summer Rain
The worst days of any summer are the rainy ones. We spend all year looking forward to nice weather and long, hot days. All of winter, with its cloudy days and bitter cold, we dream of those endless days at the beach,lying on the sand and enjoying the bright and burning sun. And then, summer comes, and it rains.
As a child, I would wake up to rainy summer days and come close to crying. It wasn&t fair. We suffered through months of school and experienced bad weather for those short ten weeks of freedom and pleasant weather.
On those rainy summer days, I had nothing fun to do and could only sit inside, staring out at the rain like a bird in a cage. I was an only child, so there was no one else to play with. My father worked from home, so I was not truly alone, but he could not actively play with me since he was at work. It was those days that I would watch whatever was on television or read any books that I could find lying around. I&d drag through the day and pray each night that the rain would not be there the next day.
As an adult, though, my opinion of summer rain has changed. When you have to work every day, summer is not as exciting. Everything seems dull. Such a mindset makes you cheer for anything new or different. I spend the winter dreaming of summer and the summer dreaming of winter. When summer comes, I hate how hot it is. And then I look forward to the rain, because the rain brings with it a cold front, which makes me comfortable. Rainy days are still the worst days of the summer, but summer rain today means positively beautiful&and considerably cooler&weather tomorrow.
56. When the author was a child, he ______.
A. hated rainy days &&&&&& &&&&&&&&&&&&& &&&&&&&&&&&&& &&&&&&&&&&&&& &&&&&&&&&&&&& B. liked staying indoors
C. preferred cooler weather&&&& &&&&&&&&&&&&& &&&&&&&&&&&&& &&&&&&&&&&&&& D. dreamed on summer days
57. We can learn from the passage that the author ______.
A. had no brothers or sisters&&&& &&&&&&&&&&&&& &&&&&&&&&&&&& &&&&&&&&&&&&& B. was often left alone at home
C. could enjoy the brilliant sun in winter &&&&&&&&&&&&& D. preferred reading to playing outside
58. As an adult, the author views summer rain differently because ______.
A. he knows it won&t last long
B. rain makes the weather cooler
C. his summer holiday is very short
D. he can better deal with his downtime
我的答案答案评定：参考答案56.A
难度评价：
做题心得：
夹叙夹议，讲述作者从小到大对夏雨的感受变迁。本文虽然读起来有些偏散文，并不像故事那种主线清晰，但题目设置非常容易。
56.A考查细节辨认题。根据题干关键词a child找到文章的对应段是第二段，其中的第一句话As a child, I would wake up to rainy summer days and come close to crying.中的关键词rainy summer days和crying判断作者讨厌夏季雨天。故答案为A。
57.A考查细节辨认题。根据文章第三段的第三句话My father worked from home, so I was not truly alone, but he could not actively play with me since he was at work排除B；根据文章第一段的第二句话All of winter, with its cloudy days and bitter cold, we dream of those endless days at the beach, lying on the sand and enjoying the bright and burning sun判断排除C；根据文章第三段的. It was those days that I would watch whatever was on television or read any books that I could find lying around排除D；根据文章第三段的对应句I was an only child, so there was no one else to play with可知作者没有兄弟和姐妹。故答案为A。
58.B考查细节辨认题。根据题干关键词as an adult找到文章对应段落是倒数第一段，其中的As an adult, though, my opinion of summer rain has changed和And then I look forward to the rain, because the rain brings with it a cold front, which makes me comfortable可知是因为雨让天气更凉爽才促使作者对夏天雨天的观点改变。故答案为B。
Everyone has got two personalities&the one that is shown to the world and the other that is secret and real. You don&t show your secret personality when you&re awake because you can control your behavior, but when you&re asleep, your sleeping position shows the real you. In a normal night, of course, people frequently change their position. The important position is the one that you go to sleep in.
If you go to sleep on your back, you&re a very . You normally trust people and you are easily influenced by fashion or new ideas. You don&t like to upset people, so you never express your real feelings. You&re quite shy and you aren&t very confident.
If you sleep on your stomach, you are a rather secretive (不坦率的) person. You worry a lot and you&re always easily upset. You&re very stubborn (顽固的), but you aren&t very ambitious. You usually live for today not for tomorrow. This means that you enjoy having a good time.
If you sleep curled up (卷曲), you are probably a very nervous person. You have a low opinion of yourself and so you&re often defensive. You&re shy and you don&t normally like meeting people. You prefer to be on your own. You&re easily hurt.
If you sleep on your side, you have usually got a well-balanced personality. You know your strengths and weaknesses. You&re usually careful. You have a confident personality. You sometimes , but you don&t often get depressed. You always say what you think even if it annoys people.
63. Which is NOT mentioned in the second paragraph about a person&s personality?
A. He or she is always open with others.
B. He or she always likes new ideas earlier than others.
C. He or she is always easily upset.
D. He or she tends to believe in others.
64. Point out which sentence is used to show the personality of a person who is used to sleeping on his or her stomach?
A. He or she is careful not to offend others.
B. He or she doesn&t want to stick to his or her opinion.
C. He or she can&t be successful in any business.
D. He or she likes to bring others happiness.
65. Which of the following may be the reason for you not to make friends with a person who sleeps curled up?
A. He or she would rather be alone than communicate with you.
B. He or she is rarely ready to help you.
C. He or she prefers staying at home to going out.
D. He or she wouldn&t like to get help from you.
66. It appears that the writer tends to think highly of the person who sleeps on one side because ___________.
A. he or she always shows kindness to people
B. he or she is confident, but not stubborn
C. he or she has more strengths than weaknesses
D. he or she often considers annoying people
With all the responsibilities we face in our daily lives, it&s often hard to get a good night&s rest. The problem really lies in the stress that many of us experience. Stress robs you of the rest that you need by putting you in a constant state of pressure and worry. There are, of course, numerous methods that can help you relax, but only a few of them give you a good night&s sleep. One of them is soothing (舒缓的)music for sleep.&&&& Sleep music is not just for promoting relaxation, it also can be used for various situations. Want to have a relaxing evening by yourself? Practice yoga in a comfortable environment? Think over something important? Then put on your favorite sleep music. Sleep music is not only suited for adults, but has also been known to be beneficial for children. Soothing music helps your children go to sleep more easily. &&&& Massage therapists (按摩治疗师)can also benefit from using soothing music for sleep in their clinics. This allows clients to benefit more from the session. For example, massage therapists can provide the relaxation of the body through their techniques, and the music helps clients ease their minds, helping them to relax deeper and feel more refreshed after the session.&&&& You&ll never run out as there are numerous artists and companies that make sleep music. Choosing the right music is important as well. Like most music that you can find and buy in stores, sleep music has different styles, sounds, and themes. There are those that are specifically targeted for relaxation, while some are intended to help you go to sleep.&&&& The great thing about sleep music is that it will be something you&ll be using for months, even years to come. If you want a deeper relaxation and better sleep, give some soothing music for sleep a try.
67. According to the text, people often don&t sleep well because _______.
A. they often hear heavy music&&&&&&&& B. they have too much stress
C. they are very tired&&&&&&&&&&&&&&&& D. they have little time to relax
68. We can learn from the text that ______.&&&A. sleep music is first used in massage
B. all the sleep music is intended to help people to go to sleep
C. clients during massage use sleep music to help them go to sleep
D. clients will feel more refreshed after the massage using sleep music
69. In the last paragraph, people are advised to______.&&&&A. have a rest to relieve the stress
B. try some sleep music to relax and have a good sleep
C. do a massage accompanied by sleep music&&&&D. choose a suitable sleep music
70. The text is written mainly for those_________.&&&&A. who stay up late&&&&&&&&&&&&&&& B. who often do massage
C. who want to get a good sleep&&&&& D. who like to listen to sleep music33.
When you are feeling unhappy or forget how great you are, these are six ways to make you feel good about yourself.
1) Look in the mirror and say to yourself, "I am a special person and there's no one in the world like me. I can do anything!" It may not sound so good, but it really works!
2) Do something nice for someone. Helping others always makes you feel good.
3) Smile! Be friendly to people you meet. Look for the good things in your friends and family.
4) Learn something new! Have you always wanted to decorate your own room or learn how to swim? Go for it! New challenges(挑战)are fun and give you a sense of accomplishment when you have finished.
5) Read and start a diary. Turn off the TV and let your imagination(想象) fly! Write down your thoughts, dreams or anything you want! Writing always helps to express your feelings.
6) Stay with your family. We all need our family time. Talk with your Mum or Dad or maybe even your cousin.
1. This passage may be taken from ______.
&&&&&&&&&&&&& A. a science book&& &&&&&&&&&&&&& B. a story book&& &&&&&&&&&&&&& C. a magazine&& &&&&&&&&&&&&& D. school rules
2. Among the four ways below, which can give you courage(勇气)?
&&&&&&&&&&&&& A. 1).&&&&&&&&&&&&& B. 2).&&&&&&&&&&&&& C. 4).&&&&&&&&&&&&& D. 6).
3. What do the underlined words in 4) "a sense of accomplishment" mean?
&&&&&&&&&&&&& A.成就感&&&&&&&& &&&&&&&&&&&&& B.忧伤感&&&&&&& &&&&&&&&&&&&& C.挫折感&&&&& &&&&&&&&&&&&& D.信任感
4. Which of the following should you say "NO" to when you are unhappy?
&&&&&&&&&&&&& A. You should always look for the good things of others.
&&&&&&&&&&&&& B. Stay alone at home as much as possible.
&&&&&&&&&&&&& C. Learn something new and go for it!&&&
&&&&&&&&&&&&& D. Keep a diary to express your feelings.
5. The best title(标题)for the passage is ______.
&&&&&&&&&&&&& A. Do Your Best&&&&&&&&&& &&&&&&&&&&&&& B. Six Ways to Feel Good about Yourself
&&&&&&&&&&&&& C. It's Never too Late to Learn&& &&&&&&&&&&&&& D. Always Smile to Your Life
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