已知sinθ+cosθ=35，则sinθ•cosθ=______．

阅读理解。

     Geography is the study of Earth and its climates. Scientists use it to study global (全球的) warming and

track (跟踪) the weather. Govemments use it to leam where people live and work and to plan what to do with

the land. It is now easier than event. use geography because of a science called space technology.

     The United States launched its first satellite in 1958. Some space missions (使命) that followed were

geographical studies. In fact, earth science is a big part of the work of the National Aeronautics and Space

Administration (NASA).

     Astronauts looked out of the space shuttle (航天飞机). They decided to take photographs of Earth from

their vantage point. Over the years, picture quality improved. Shuttle photography now shows land features,

such as rivers. It can even show the streets oflarge cities. Photos of the same places at different times show

how the land is changing.

     NASA does not use just photographs, though. In 1958 it launched TIROS (the Television Infrared

Observation Satellite). This first use of a satellite to study Earth was effective (有效的) in giving weather

forecasts. It led to the creation of new space tools to use in geography.

     The Landsat Program began in 1972. This satellite sent detailed (细致的) views of Earth from space. The

pictures were so precise (精确) that scientists could count the number and kinds of crops in a field. Landsat

showed where Earth's surface had faults along which earthquakes might happen. This information helped in

the planning of new cities and factories. Landsat also made discoveries. In Antarctica it located ranges of

unknown mountains. It pinpointed small lakes in Virginia that were not on maps. Landsat, now more advanced,

still flies today.

     Another space tool is Earth Observing - 1 (EO - 1). This spacecraft fiies right behind Landsat. It takes

pictures of the same sites. The two sets of pictures, viewed together, show how cities grow and how other

places, such as rain forests, become smaller over time. This helps scientists learn how people affect (影响)

geography.

     One of the newest space tools is the Geographical Information Systems ( GIS). CIS is computer software

that helps scientists to study Earth. CIS is different from ear- lier space tools. Businesses, schools, and even

average people-not just the government-can use it to show them how changes in the planet might affect

them.

1. Why do govemments study geography according to the passage? 

A. To improve the environment.

B. To make the land use plan.

C. To make new discoveries.

D. To count the crops in a field.

2. Which of the following is true according to the passage?

A. The U. S. satellite program began in 1972.

B. Landsat was able to take pictures of other planets.

C. TIROS was successful in giving weather forecasts.

D. GIS can only be used by the govemment.

3. EO -1 takes photographs of the same places as Landsat because  _______.

A. the two groups of pictures can show the changes of Earth

B. EO - 1 is practicing for future photography missions

C. Landsat is out of date and new pictures are needed

D. Landsat can't send detailed views of Earth from space

4. From the passage, we can infer that _______.

A. GIS is the newest computer to study Earth

B. NASA only depends on photos to study Earth

C. satellite pictures can give more detailed informations

D. recent U. S. satellites are as advanced as the old ones

    青藏高原是全球海拔最高的独特地域单元。它的隆起是数百万年来地球史上重大的事件之一。读青藏高原隆起前后大气环流图和相关材料，完成下列问题。

材料一：无青藏高原时的环流状况

如图所示，跨过定滑轮的细线的一端系着放置在倾角为30°的斜面上的木块A，另一端系着穿在竖直杆上的木块B．开始时木块B与定滑轮等高，木块B到定滑轮间的距离为4m．求：放手后，当木块B下降3m后的瞬间，木块A和木块B的速度大小之比为（　　）

A．1：1

B．5：3

C．3：5

D．4：5

45岁，男性，到我院体检，无脱水貌，测体温36．5℃，体重70kg，心率75次／分，律齐，有力

其机体每日产生非挥发性酸为（）

A.150mmol

B.40～60mmol

C.0.2mmol

D.20～40mmol

E.15000mmol

关键零件的尺寸应反复测量（）直到数据稳定可靠。

A.1次

B.2次

C.3次

D.若干次