平坦地形条件下，风廓线通常满足（）。A.线性分布 B.指数分布 C.对数分布 D.正

提交投标文件的投标人少于三个的，招标人应当依法重新招标。重新招标后投标人仍少于三个的，必须招标的工程建设项目，报有关行政监督部门备案后可以不再进行招标，或者对两家合格投标人进行开标和评标。

临床医学研究中的保密原则（）

A.欺骗、威胁、利诱进行医学临床实验违反了道德和法律

B.负担和受益要公正分配

C.受试者与研究者之间应保密

D.死亡家属有权获得赔偿

E.需获得伦理专家委员会（或主管部门）的批准

阅读理解

     Stubbornness can push an entrepreneur (企业家) to hold on but it can also kill a business if it gets

too extreme.

     Because I'm stubborn, I realized my dream of creating a petfood company. Our foods include organic

fruits, vegetables and meats. At first we packaged our foods in transparent bags, as it was part of our

guiding philosophy.

     To start the company in 2003, I visited every petfood store in Manhattan and some outside the city.

In 2007 I moved the company to Muskego, Wis., and our earnings were almost $500,000 that year. But

getting my products into stores was just the beginning. We were competing against much bigger petfood

companies whose monthly marketing budgets were more than our yearly sales. So we invested in

advertising and a website.

     With more customers came more feedback, much of which I dismissed. I was also receiving

complaints about ice crystals (晶体) on the food, which form when the air temperature changes during

transport. For this reason, most frozen foods are packaged in opaque (不透明的) bags or boxes.

Studies have proved that ice crystals have little, if any, effect on either the quality or the taste of the food.

So I ignored the complaints. After all, I told myself, we were better than competitors that wouldn't even

show their products. We didn't hide anything.

     In 2007 our sales kept growing, but not as fast as those of our competitors. We were told that new

consumers were choosing products packaged in opaque bags. When I visited the stores and forced

myself to consider my products objectively, I had to agree:The ice crystals destroyed the look I wanted.

We switched to opaque bags and tried to make the ice crystals smaller. Customers responded:In 2009

our products were sold in 2,500 stores across the country.

1. What was the author's purpose of packaging their foods in transparent bags at first?

A. To make their foods look attractive.

B. To show their guiding philosophy to consumers.

C. To make sure that their foods could be seen clearly.

D. To show that their foods were environmentally friendly.

2. Why did the author invest in advertising and a website?

A. Because few people knew about their products.

B. Because his company faced great challenges.

C. Because he wanted to move his company to Muskego.

D. Because his company was about to close down.

3. According to the passage, ice crystals ________.

A. only appear in frozen foods

B. may make pets feel uncomfortable

C. won't form if pet food is transported well

D. have little effect on the quality of pet food

4. The author's company switched to opaque bags because ________.

A. consumers disliked seeing ice crystals

B. opaque bags helped reduce ice crystals

C. foods in opaque bags are easy to keep fresh

D. opaque bags are cheaper than transparent ones

5. This passage was written mainly to show that ________.

A. people shouldn't let stubbornness stop them from taking advice

B. stubbornness can make people succeed or fail

C. the road leading to success is full of difficulties

D. stubbornness always leads to failure

在有关总需求和总供给的研究中，常使用就业量不变的总量生产函数。（）

加热炉燃料气压力控制阀故障后应当（）

A.切到旁路阀控制

B.立即停车

C.检查压力控制表

D.在线检查故障原因