问题 问答题

如图甲所示,取一块硬纸板在相对的顶点附近各开一个小孔,  用细线系住,细线的另一端跨过桌边定滑轮各悬挂一个50 g的钩码.  

(1)此时纸板受到的两个拉力的大小有什么关系?方向有什么关系?纸板能否静止? 

(2)把纸板扭转一下,使纸板的一边与桌面平行(图乙所示).此时纸板还能平衡吗?

(3)在其中一个钩码下端再挂一个50g的钩码.纸板还能平衡吗?  

(4)通过实验得出的结论是什么?

答案

(1)大小相等;方向相反;可以静止.

(2)不能.

(3)不能. 

(4)平衡力大小相同,方向相反,作用在同一直线上。

阅读理解

阅读理解。

    There are many wetlands in China and some of them have become the world's important wetlands. The

Chinese Yellow Sea Wetlands are among them. They are in Yancheng, Jiangsu Province. They are home for

many different kinds of birds and animals. The world's largest Milu Deer Nature Reserve is in them. More

than 700 milu deer live freely there. There are not many red-crowned cranes in the world, but every winter

you can see some in the Red-crowned Cranes Nature Reserve in the Yellow Sea Wetlands.

    The temperature in the wetlands is usually neither too high nor too low. There is a lot of rain and sunshine,

too. They are really good places for wildlife. Offering food and home for some special kinds of animals and

birds is not the only reason why we need to protect wetlands. Wetlands are important because they also

prevent flood. But some people want to change the wetlands to make more space for farms and buildings.

This means there will be less and less space for wildlife.

    Luckily, more and more people are beginning to realize the important of wetlands and wildlife. Every year,

on February 2nd, many activities are held to tell people more about wetlands.

1. The Chinese Yellow Sea Wetlands are in the            of China. [ ]

A. east

B. south

C. west

D. north

2. The World Wetlands Day is on           . [ ]

A. April 22

B. June 25

C. February 2

D. March 22

3. We must protect wetlands because           . [ ]

A. they are home for wildlife

B. they can prevent flood

C. they can offer food to the animals and birds

D. all of the above

4. The best title for the passage is           . [ ]

A. China's Wetlands Have All Entered the World's List

B. Wetlands-Home for Wildlife and Human Beings

C. Special Animals in the Chinese Yellow Sea Wetlands

D. Wetlands-Valuable Recourses (珍贵资源) of Land on the Earth

阅读理解与欣赏

       信钓于城下,诸母漂,有一母见信饥,饭信,竟漂数十日。信喜,谓漂母曰:“吾必有以重报母。”母怒曰:“大丈夫不能自食,吾哀王孙而进食,岂望报乎!”淮阴屠中少年有侮信者,曰:“若虽长大,好带刀剑,中情怯耳。”众辱之曰:“信能死,刺我;不能死,出我胯下。”于是信孰视之,俯出胯下,蒲伏。一市人皆笑信,以为怯。 …… 信至国,召所从食漂母,赐千金。召辱己之少年令出胯下者以为楚中尉。告诸将相曰:“此壮士也。方辱我时,我宁不能杀之邪?杀之无名,故忍而就于此。” (《史记·淮阴侯列传》)

〔注〕①漂:在水里冲洗丝棉之类。②竟:到底,完毕。③王孙:公子,少年。对年轻人的敬称。

④中情:内心。⑤能死:不怕死。⑥国:都城。指下邳。⑦无名:没有意义。

1.解释下列句中划线的词。

(1)信:______________________

(2)于是信视之:______________ 

(3)吾王孙而进食:______________

(4)以为怯:_________________

2.选出与例句中划线字意义和用法相同的一项

      例句:吾哀王孙进食[ ]

A.黑质白章(《捕蛇者说》)        

B.云归岩穴暝(《醉翁亭记》)

C.拔山倒树来(《幼时记趣》)    

D.足肤皲裂不知(《送东阳马生序》)

3.用现代汉语写出文中句子的意思。

     方辱我时,我宁不能杀之邪?杀之无名,故忍而就于此。 

                                                                                                                                                 

4.读了上文后,你觉得韩信具有怎样的性格特点?请用自己的话简要概括。