如果在交易日( )前处于停牌状态的证券，上海证券交易所不受理其大宗交易的申报。 A．

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                                                                     Study Books

     Basic Study Manual Hardcover: $37

     Future success depends on the ability to learn. Here are the answers to the questions most often

asked by parents, teachers, business trainers and by students themselves. Read this book and learn:

    What the three barriers (障碍) to study are and what to do about them.

    What to do if you get tired of a subject you are studying.

    Twenty-six simple drills to help you learn how to study easily, rapidly and with full understanding.

    Buy and read the Basic Study Manual and use it to dramatically improve your ability to study.

    Study Skills for Life Hardcover: $32

    L Hubbard's study technology for teenagers opens the door to their future success by giving them the

ability to study and learn. Fully illustrated (加插图于) for easy understanding.

    Learning How to Learn Hardcover: $25

    The basics of effective study for 8-to-12-year-old, fully illustrated. Children who read and apply the

materials in this book regain their liking for study and their ability to apply this knowledge in life. Get this

book for a child you want to see win at his studies!

    How to Use a Dictionary Picture Book for Children Hardcover: $36

    In spite of billions of dollars spent on "educational research", children are not taught the most basic

skills of learning, even the most basic of these: how to use a dictionary. In fact, a search of educational

books for children found no book that told them how to use a dictionary or that one should. Written for

children 8-12-year-old, this fully illustrated book will teach your child:

    How to find words in a dictionary.

    The different ways that words are used.

    What the different marks and symbols that are used in a dictionary mean.

    How to use a dictionary to correctly pronounce words.

It includes a section for parents and teachers showing you how to use this book with children. Buy this book and give it to your children to unlock their education. What's more, you'll just pay 50% for it before May 1, 2007.

1. Some of the four books were illustrated in order to _________.

A. help readers understand them    

B. persuade readers to buy them

C. reduce the cost of them

D. make them suitable to different readers

2. If you buy the four books on April 30, 2007, you will have to pay _________ for them.

A. $130  

B. $112

C. $65  

D. $18

3. The purpose of the passage is to _________.

A. show to readers how to use the four books

B. help children to learn English

C. enrich students' knowledge about nature

D. sell the four books to students

(2011年上海浦东模拟)一辆汽车质量为1×10³ kg，最大功率为2×10⁴ W，在水平路面上由静止开始做直线运动，最大速度为v₂，运动中汽车所受阻力恒定．发动机的最大牵引力为3×10³ N，其行驶过程中牵引力F与车速的倒数的关系如图所示．试求：

(1)根据图线ABC判断汽车做什么运动？

(2)v₂的大小；

(3)整个运动过程中的最大加速度；

(4)匀加速运动过程的最大速度是多大？当汽车的速度为10 m/s时发动机的功率为多大？

增大飞机的翼展可以减小飞机的什么阻力？

天文学家一直假设，宇宙中的一些物质是看不见的。研究显示；许多星云如果都是由能看见的星球构成的话，它们的移动速度要比任何条件下能观测到的快得多。专家们由此推测：这样的星云中包含着看不见的巨大物质，其重力影响着星云的运动。
以下哪项是题干的议论所假设的
Ⅰ．题干说的看不见，是指不可能被看见，而不是指离地球太远，不能被人的肉眼或借助天文望远镜看见。
Ⅱ．上述星云中能被看见的星球总体质量可以得到较为准确的估计。
Ⅲ．宇宙中看不见的物质，除了不能被看见这点以外，具有看得见的物质所有属性，例如具有重力。

A．只有Ⅰ和Ⅱ。

B．只有Ⅰ和Ⅲ。

C．只有Ⅱ和Ⅲ。

D．Ⅰ、Ⅱ和Ⅲ。

（）适用于在渗透系数很低的淤泥层中测定孔隙水压力。

A.立管式测压计

B.水压式测压计

C.电测式测压计

D.气动测压计