利用电离层能反射频率在（）频段的短波，从而进行较长距离和大范围通信的方式称为短波无线

今天的中国正在走向富强，我们不能忘记那些曾为挽救民族危亡做出贡献的仁人志士。下图人物是近代著名的状元企业家，他是

A．詹天佑

B．曾国藩

C．张謇

D．荣宗敬

赵立国与余庆华合伙承包村里的水塘养虾。水塘的上游有一家集体造纸厂。2003年5月，赵立国、余庆华二人向水塘投放虾苗2万尾。投放后赵、余二人精心管理，日夜看护。10天后，二人发现塘内有少量的死虾出现，当即捞起部分死虾送造纸厂与其交涉。造纸厂派人到现场了解情况。经双方估算，塘内漂浮和打捞上岸的死虾约5000尾。厂方把死虾送市商品检验处化验，化验结论是虾苗死亡可能是排出的废水毒死，但不能肯定。市环保部门对造纸厂排出废水的检验结果是该厂排出的废水量没有超过国家规定的排污标准。由于赵、余二人与造纸厂之间关于赔偿问题不能达成一致意见，二人遂向法院起诉，要求赔偿损失。在举证期间内，原告赵立国、余庆华二人提供的证据材料有：(1)2003年5月10日购买2万尾虾的发票，发票载明了单价及总金额；(2)原告与村里签订的承包合同；(3)估算死虾 5000尾的书面材料，原告及被告派到现场查看人员都在上面有签名；(4)赔偿费用一览表及计算方法； (5)李某的证言，证明在送检过程中商品检验处的检验员蔡某与厂方有过两次私下的接触。李某后到庭作证。被告造纸厂不同意赔偿，提出，了以下证据材料：(1)市商品检验处的化验报告；(2)市环保部门的检验报告。在诉讼过程中，原告提出申请重新鉴定虾的死亡原因，法院指定由省级有关部门做出了新的鉴定结论。 问题：

原告应对哪些事实负举证责任

第三部分：阅读理解（共20小题；每小题2分，满分40分）

阅读下列短文，从每题所给的四个选项（A、B、C和D）中，选出最佳选项。

Everybody has had at least one experience from which he knows the meaning of life. This time, which took place several years ago, but seems as if it just happened.

On an afternoon several years ago, my brother-in-law opened the bottom drawer of my sister’s dress and picked out a beautiful skirt. “ Jan bought this the first time we went to New York, at least 8 or 9 years ago. She never wore it. She was saving it for a special occasion.” he said．I guess this was the occasion: it was the funeral of my sister, after her unexpected death.

He took the shirt and put it on bed, with the other clothes we were taking to the funeral. Then he closed the drawer and turned to me, “Don’t ever save anything for a special occasion. Every day you’re alive is a special occasion.”

I’m thinking about his words, and they’ve changed the way I live my life. I’m spending more time with my family and friends and less time in committee meetings. Whenever possible, life should be a kind of experience to enjoy, not to suffer. “Someday ”and “one of these days ”are losing their importance  on my vocabulary. If it’s worth seeing or hearing or doing, I want to see and hear and do it now.

Ever since that day, I have been trying very hard not to put off, hold back or save anything that would add laughter and color to our lives. Every morning when I open my eyes, I tell myself that every day, every minute, every breath, truly is a gift. So cherish every day and find the true meaning of your life.

56．Why did Jan buy the beautiful skirt but didn’t wear it?

A．She waited for a special occasion to wear it on.

B．She wanted to keep it for someone else.

C．She saved it till she grew up.

D．She would give it to herself as a gift some day.

57．What does the underlined word “cherish” mean?

A．Treasure.  B．Waste.      C．Own. D．Save

58．From his experience, the author learns that_______.

A．everybody can have a happy life through efforts

B．every day in our lives is worth cherishing

C．enjoying ourselves is the most important thing in our lives

D．everybody will have some things left to do after his death

59．What does the author write this passage for?

A．To show how to make good use of everyday in life.

B．To explain the true meaning of his brother-in-law’s words.

C．To tell people to cherish every day and find the meaning of life.

D．To encourage people to waste time and enjoy themselves in life.

60．What’s the best title for this passage?

A．Every Day IS a Gift      

B．My Sister Jan

C．What Is the Meaningful Life like   

D．The Most Important Time in Your Life

下列程序的输出结果是_____ 。　　int ast(int x,int y,int * cp,int * dp)　　{ *cp=x+y; *dp=x-y; }　　main()　　{ int a=4,b=3,c,d;　　ast(a,b,&c,&d);　　printf("%d,%d/n",c,d); }

737-800空调区域温度配平空气调节活门的作动原理是什么（）

A.电机作动

B.双金属弹簧，随温度保持一定开度

C.电控启动活门