将大桥的结构进行简化，取其部分可抽象成如图丁所示的模型，（_爱下问搜题

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问题探究题

将大桥的结构进行简化，取其部分可抽象成如图丁所示的模型，

（1）可以看出它用到了的相关知识．其中O是，代表桥重和过往车辆等产生的对桥的作用力。

（2）为了减小钢索承受的拉力，在需要与可能的前提下，可以适当增加塔桥的高度。请分析原因。

（3）假如让你来设计新的斜拉索式大桥，你还能提出什么方法可以减轻钢索承受拉力？（说出一种方法即可）

答案

（1）杠杆；支点；F₁

（2）增加桥塔的高度，可以增大拉力的力臂，拉力会随之减小（合理即可）

（3）使用新型材料，减小桥自重。（其它合理也可）

阅读理解

Read and choose. (阅读短文，判断正误，正确的画“√”，错误的画“×”)

Come on, everybody. The party in the zoo is beginning now. Let's welcome

our Mr Elephant. Look, he has a long nose. Oh, he can eat many grapes. And the

next one (下一个) is our Miss Giraffe. She has a long neck. Our cute Rabbit has

two long ears. And he likes carrots very much. Oh, where are his carrots? On the

desk? No. Under the chair? No. Oh, they're here. The carrots are under the table.

Mr Deer plays the violin very well.

( ) 1. There is a party in the zoo.

( ) 2. The elephant likes oranges very much.

( ) 3. The giraffe has a short neck.

( ) 4. The rabbit doesn't find his carrots at last (最后) .

( ) 5. The carrots are under the bed.

( ) 6. The deer can play the violin.

单项选择题

关于产品缺陷责任，下列哪一选项符合《产品质量法》的规定( )。

A．基于产品缺陷的更换、退货等义务属于合同责任，因产品缺陷致人损害的赔偿义务属于侵权责任

B．产品缺陷责任的主体应当与受害者有合同关系

C．产品缺陷责任一律适用过错责任原则

D．产品质量缺陷责任一律适用举证责任倒置