问题 操作题

按照题目要求作图:

(1)如下图甲所示,某人站在A处用一根绳子和两个滑轮提起物体B,画出最省力的绕线.

(2)如下图乙所示,是用螺丝坩撬图钉的示意图,画出动力F1的力臂l1和阻力F2的示意图;

(3)如图丙所示是一侧带有书柜的办公桌,现在要用一个最小的力将其一端稍抬离地面.请画出这个力的方向(保留作图痕迹),并用“O”标明这个“杠杆”的支点.

答案

(1)

(2)

(3)

选择题
阅读理解

阅读理解。

     Name:Off the Beaten Path

     Cover price:$30.00

     Our price:$19.80

     The best-selling Reader's Digest travel book has 40% new content including over 200 new sites,

over 200 new full-color photographs, and all-new, up-to-date maps. It focuses on more than 1, 000

of the United States' most overlooked must-see destinations.

     Name:Container Gardens by Number

     Cover price:$ 15.95

     Our price:$9.49

     A unique book contains 50 easy-to-follow container designs. Each design provides a simple

numbered planting plan that shows exactly how to create each display, with an instruction of the

finished planter and in-depth plant information. The plans are easy to follow and for any type of living

space or garden.

     Name:Best Weekend Projects

     Cover price:$ 17.95

     Our price:$13.96

     Choose from 80 unique ideas to create an extraordinary living space. The projects are practical,

as well as attractive, and will improve your home and yard and can be made in a weekend. These 80

well-designed projects are presented in a clear, easy-to-follow style that addresses readers in an

accessible, user-friendly tone.

     Name:l80l Home Remedies(治疗方案)

     Cover price:$ 40.00

     Our price:$ 29.96

     Plenty of health complaints can be handled at home. Each and every remedy will be tested by a

doctor to make sure it is safe and sound.

     Dozens of conditions are covered, from headaches, sunburn, bad breath, and blisters(起泡;起疮)

to allergies, and hiccups(打嗝).

1. You can most probably read the passage in a ________ .

A. travel guide                  

B. medicine booklet

C. textbook                    

D. newspaper

2. How much money could you save if you want to buy a travel book?

A. $10. 20.          

B. $6.46.

C. $13.96.

D. $19.80.

3. Which of the following could help you to deal with common diseases without a doctor?

A. Off the Beaten Path.            

B. Container Gardens by Number.

C. 1801 Home Remedies.          

D. Best Weekend Projects.

4. Which of the following is NOT true according to the passage?

A. Container Gardens by Number can help you improve your gardening skills. 

B. Off the Beaten Path covers about 1, 000 famous traveling sites all over the world.

C. Best Weekend Projects may be useful for you to modify your living room.

D. 1801 Home Remedies is designed for home use.

5. What's the purpose of the passage?

A. To advise readers to buy their books.

B. To advise readers to read more in spare time.

C. To share the pleasure of reading with readers.

D. To share his opinion about the books with readers