なぜテストをするかというと、テストがないととかく学生はなまけ（）になるからだ。 A.

物业管理投诉处理的方法包括( )。

A．详细记录，确认投诉

B．真诚对待，冷静处理

C．耐心倾听，不与争辩

D．及时处理，注重效率

E．总结经验，加强管理

如图，一根轻质杠杆可绕O点转动，在杠杆的中点挂一重物G，在杆的另一端施加一个方向始终保持水平的力F，力F使杠杆从所示位置慢慢抬起到水平位置的过程中，力F将如何变化？请说明理由．

阅读理解。

     Everglades National Park is the most endangered national park in America. The purpose of making a

national park is to protect the plants and animals that live there. But things that happen outside the park

also affect the life within it.

     Everglades National Park is part of a much larger area known as the Everglades. At one time, water

flowed freely in the Everglades. During the rainy season, water would fill the Kissimmee River. Then it

flowed into Lake Okeechobee. Once the lake became full, water spilled over onto the flatland. From there

a shallow sheet of water moved slowly down the Florida Peninsula. Then it emptied into Florida Bay. This

shallow sheet of water was the Everglades River. It was only a few inches deep. But it was up t0 50 miles

wide and over 100 miles long.

     The Everglades is home to many plants and animals found nowhere else in the world. Today, some of

these plants and animals are in danger of disappearing forever.

     The main reason is that the Everglades is no longer a free-flowing river. Canals have been built to drain

(排干) most of the shallow river. People have also built a dam to hold back water from Lake Okeechobee.

Most of the water from the Everglades is trapped in man-made lakes. Cutting off the flow of water into

Everglades National Park has done more harm than good. Now it threatens the wildlife in the park.

     Water pollution is another reason some plants and animals are disappearing. Years ago, large areas of the

Everglades were drained and turned into farmland. Today the fertilizers (肥料) used on crops are polluting

the water. The "river of grass" is slowly disappearing. Many kinds of plants are disappearing. Animals that

depend on these plants for food no longer have anything to eat.

     The problems facing Everglades National Park are very serious. But there is still hope. Work is already

under way to save the Everglades. The federal government, the state of Florida, and several other groups

are all working together to try to undo the damage.

1. Why was a national park built in America? 

A. To protect people.

B. To protect the plants and animals.

C. To provide a fun place for people.

D. To keep animals from going in the park.

2. The second paragraph mainly tells us _____.

A. how water flowed into the Everglades River

B. how big Everglades River was

C. what the Everglades used to be like

D. what happened to Everglades River during the rainy season

3. The main reason for the animals being endangered is that _____.

A. there's no rain there now

B. people cut the plants that the animals feed on

C. large areas of Everglades were turned into buildings

D. the water flowing into the Everglades has been cut off

4. From the end of the passage, we know that _____.

A. nobody takes care of the Everglades

B. some measures are being taken to protect the environment of Everglades

C. the environment of Everglades will be worse and worse

D. the government is worried about Everglades but has no way

李先生正在考虑投资三种共同基金。第一种是股票基金；第二种是长期政府债券与公司债券基金；第三种是收益率为8％的短期国库券货币市场基金。这些风险基金的概率分布如表5—6所示。基金的收益率之间的相关系数为0．10。下表风险基金期望收益与标准差

如果某投资者对他的资产组合的期望收益率要求为14％，并且要求在最佳可行方案上是有效率的，那么该投资者资产组合的标准差是（）

A.11.28％

B.12.36％

C.13.04％

D.14.36％