（本題12分）根據(jù)空氣質(zhì)量指數(shù)API（為整數(shù)）的不同，可將空氣質(zhì)量分級(jí)如下表：

對(duì)某城市一年（365天）的空氣質(zhì)量進(jìn)行監(jiān)測(cè)，獲得的API數(shù)據(jù)按照區(qū)間，，，，，進(jìn)行分組，得到頻率分布直方圖如圖.                         

（1）求直方圖中的值；

（2）計(jì)算一年中空氣質(zhì)量為良的天數(shù)；

（3）某環(huán)保部門準(zhǔn)備在一年內(nèi)隨機(jī)到該城市考察兩次空氣質(zhì)量，求兩次考察空氣質(zhì)量都為良的概率（結(jié)果用分?jǐn)?shù)表示）．

（1）  …… 4分

（2）146天；     …… 8分

（3）  …… 12分


解析:

略

練習(xí)冊(cè)系列答案
相關(guān)習(xí)題

科目：高中英語(yǔ) 來源： 題型：

當(dāng)今社會(huì)已經(jīng)進(jìn)入信息時(shí)代,交往已經(jīng)成為人們生活中必不可少的部分。請(qǐng)你從下圖提供的三種交流方式中選出你最喜歡的一種，并陳述理由。

letter                    cellphone                        E-mail

        

注意: 1. 詞數(shù)120左右;

     2. 開頭已為你寫好, 不計(jì)入總詞數(shù)。

   

My favorite way of communication

    As we all know，communication has been playing an important part in people’s life.

 

                                                                        

 

                                                                       

 

                                                                       

 

                                                                         

 

                                                                          

查看答案和解析>>

科目：高中英語(yǔ) 來源： 題型：閱讀理解

Have you ever been in a meeting while someone was making a speech and realized suddenly that your mind was a million miles away? You probably felt sorry and made up your mind to pay attention and never have daydreaming again. Most of us, from earliest school days, have been told that daydreaming is a waste of time.

“On the contrary, “says L. Giambra, an expert in psychology (心理學(xué)), “daydreaming is quite necessary. Without it, the mind couldn't get done all the thinking it has to do during a normal day... You can't possibly do all your thinking with a conscious(有意識(shí)的)mind. Instead, your unconscious mind is working out problems all the time. Daydreaming then may be one way that the unconscious and conscious states of mind have silent dialogues. “

Early experts in psychology paid no attention to the importance of daydreams or even considered them harmful. At one time daydreaming was thought to be a cause of some mental illnesses. They did not have a better understanding of daydreams until the late 1980s. Eric Klinger, a professor of psychology, is the writer of the book Daydreaming. Klinger says, “We know now that daydreaming is one of the main ways that we organize our lives, learn from our experiences, and plan for our futures. Day dreams really are a window on the things we fear and the things we long for in life. “

Daydreams are usually very simple and direct, quite unlike sleep dreams, which may be hard to understand. It's easier to gain a deep understanding of your life by paying close attention to your daydreams than by trying to examine your sleep dreams carefully. Daydreams help you recognize the difficult situations in your life and find out a possible way of handling(處理) them.

Daydreams cannot be predicted(預(yù)料); they move off in unexpected directions which may be creative and full of useful ideas. For many famous artists and scientists, daydreams were and are a main source of creative energy.

So the next time you catch yourself daydreaming, don't stop. Just pay attention to your dream. It may be more important than you think.

Daydreaming used to be considered      .

       A. very simple and direct             B. unimportant or even harmful

       C. a necessary part of thinking      D. the result of an unconscious mind

In what way are daydreams different from sleep dreams?

       A. Daydreams help us to handle more difficult situations.

       B. Daydreams are not so easy for us to control and direct.

       C. Daydreams are easier for us to understand.

       D. Daydreams help to develop an unconscious mind.

Professor Eric Klinger believes that      .

       A. we may study our experiences just through our daydreams

       B. daydreaming is one of the important ways that we recognize our lives

       C. our fears and longings in life are shown in our daydreams

       D. we should be able to tell our futures by having daydreams

The writer of the article thinks that      .

       A. daydreaming is more helpful than sleep dreams

       B. daydreaming with an unconscious mind will do good to health

       C. Professor Eric Klinger has a better idea than L. Giambra

       D. many artists and scientists are famous because they have daydreams

Which of the following is NOT TRUE according to the passage?

       A. Daydreaming was once regarded as a cause of some mental illnesses. 

       B. Many well-known artists gained energy of creation from daydreams.

       C. Experts began to have a better understanding of daydreams in the late 1980s.

       D. Scientists believe that we can know daydreams before having them.

查看答案和解析>>

科目：高中英語(yǔ) 來源： 題型：

三. 句型轉(zhuǎn)換 ( 10分)

   1. If we want to lose weight, we must go on a diet.

     We must have a _________________ _____________ to keep healthy. 

   2. The blind man made a living by begging on the roadside.

     The blind man ___________ ________ _________ by begging on the roadside.

   3. You have become fatter than before; I think you should lose weight. 

     You have _________ ________ _____________; I think you’d better lose weight.

   4. Eating more vegetables will benefit you a lot.

     Eating more vegetables will ___________ ___________ ___________ to you.  

   5. Having watched TV for too long, I felt it boring.

     Having watched TV for too long, I __________ ____________ ________ it.

查看答案和解析>>

科目：高中英語(yǔ) 來源： 題型：閱讀理解

第三部分：閱讀理解（共25小題，每題2分，滿分共50分）

第一節(jié)：閱讀下列短文，從每題所給的四個(gè)選項(xiàng)（A、B、C和D）中，選出最佳選項(xiàng).

During the summer holidays there will be a revised(修改過的)schedule(時(shí)刻表 )of services for the students. Changes for dining-room and library service hours and for bus schedules will be posted on the wall outside of the dining hall. Weekly film and concert schedules which are being arranged will be posted each Wednesday outside of the student club.

　　In the summer holidays, buses going to the town center will leave the main hall every hour on the half hour during the day. The dining room will serve three meals a day from 7:00a.m. to 7:00p.m.during the week and two meals from noon to 7:00p.m. on weekends. The library will continue its usual hours during the week but have shorter hours on Saturday and Sundays. The weekend hours are from noon to 5:00p.m.

　　All students who want to use the library borrowing services must have a new summer card. This announcement will also appear in the next week’s student newspaper.

61. At which of the following times will the bus leave the main hall?

　　A.8:00, 9:00, 10:00, 11:00　　       B.8:30, 9:30, 10:30, 11:30

　　C.8:30, 9:00, 9:30, 10:00　    　    D.8:00, 9:30, 11:00, 12:30

62. Times for films and concerts are not listed in this announcement because_____.

　　A. they are not to be announced 　　　B. they are hard to arrange

　　C. the full list is not ready 　　　　  D. the full list is too long

63. In the summer holidays, the library will have_____.

　　A. no special hours　　　　　　　　 B. special hours on weekdays

　　C. special hours on weekends 　　　  D. special hours both on weekdays and weekends

64. We may infer that during the summer holidays_____.

　　A. the student newspaper will sell more copies

　　B. there will be a concert or a film once a week

　　C. many students will stay in the university

    D. no breakfast will be served on weekends

查看答案和解析>>

科目：高中英語(yǔ) 來源： 題型：

 It was _______ the exam results were known _______ a lot of time on computer games.

       A. not until; did the boy begin to regret having wasted  

B. until; that the boy began to regret to have wasted

       C. not until; that the boy began to regret wasting      

D. until; did the boy begin to regret to waste

查看答案和解析>>

科目：高中英語(yǔ) 來源： 題型：

       I will give you my friend’s home address, _____I can be reached most evenings.

A.    Which    B. when    C.whom    D.where

查看答案和解析>>

科目：高中英語(yǔ) 來源： 題型：

 We should consider what use can be made ______ such a material(材料).

   A. of               B. from              C. up               D. in

查看答案和解析>>

科目：高中英語(yǔ) 來源： 題型：

 You needn’t take your shoes off when you enter someone’s house in Australia , _____ , of course , they’re very dirty .

   A. if    B. except   C. when   D. unless

查看答案和解析>>

同步練習(xí)冊(cè)答案