能简算的要简算. 15÷13+45×11334×25÷34×256-229+17

题型:解答题

问题:

能简算的要简算.
1
5
÷13+
4
5
×
1
13
3
4
×
2
5
÷
3
4
×
2
5
6-2
2
9
+1
7
9
5×32×12.5.
考点:分数的简便算法
题型:解答题

浓硫酸具有强(),所以常温下可用铁贮存。

题型:解答题

如图甲所示,变压器原副线圈的匝数比为3:1,L1、L2、L3、L4为四只规格均为“9V,6W”的相同灯泡,各电表均为理想交流电表,输入端交变电压u的图象如图乙所示.则以下说法中正确的是( )

A.电压表的示数为36V

B.电流表的示数为2A

C.四只灯泡均能正常发光

D.变压器副线圈两端交变电流的频率为50Hz

题型:解答题

阅读理解。

     At Dallm/Fort Worth Airport, the lights are controlled by sensors that measure sunlight. They dim

immediately when it's sunny md brighten when a passing cloud blocks the sun.

     A wall of windows at a University of Pennsylvania engineering budding has built-in blinds (百页窗)

controlled by a computer program that follows the sun's path.

     Buildings are getting smarter-and the next generation of building materials expected to do even more.

     Windows could catch the sun's energy to heat water. Sensors that measure the carbon dioxide breathed

out by people in a mom could determine whether the air conditioning needs to be turned up.

     Many new materials and technology have been designed in the last 15 years. They now being used in a

wave of buildings designed to save as much energy as possible. They include old ideas, like"green roofs,"

where a belt of plants on a roof helps the building keep heat in winter and stay cool in summer, and new

ideas, like special coating for windows that lets light in, but keeps heat out.

     As technologies such as sensors become cheaper, their uses spread.

     The elevators (电梯) at Seven World Trade Center, which is under construction in New York, use a

system that groups people traveling to nearby floor into the same elevator, thus saving elevator stops.

People who work in the building will enter it by swiping (刷) ID cards that will tell the elevators their floor;

readouts will then tell them which elevator to use. The building also has windows with a coating that blocks

heal while letting in light.

     More new building materials and technology are in development. A Philadelphia building farm is now

working on"smart wrap" that uses tiny solar collectors to catch the sun's energy and transmitters (传感器)

the width of a human hair to move it. They are expected to change the face of the construction industry in

the next ten years or so.

1. ____ will be developed and used in the construcction industry.

A. "Green mops" that cool or heat buildings

B. "Smart wrap" that catches the sun's energy

C. Sunlight-measuring sensors that control lights

D. Window coating that lets light in, but keeps heat out

2. The elevators at Seven World Trade Center are special because they can _____.

A. send people to floors with fewer stops

B. teach people how to use their ID cards

C. make people stay very cool in summer

D. help people go traveling in the building

3. The underlined word "it' in the last paragraph refers to _____.

A. a human being

B. smart wrap

C. the sun's energy

D. a transmitter

4. What might be the most suitable title for the text?

A. Buildings Are Becoming Smarter

B. Buildings Are Getting More Sunlight

C. Buildings Are Lacking in Much Energy

D. Buildings Are Using Cheaper Materials

题型:解答题

以下属于证券经营机构的禁止行为的有( )。

A.非法获取内幕信息的人利用内幕信息买卖证券

B.在自己实际控制的账户之间进行证券交易

C.证券经营机构将自营业务和经纪业务分开管理和操作

D.委托其他证券公司代为买卖证券的行为

题型:解答题

()布置处,应标有明显的写有中.英文名称的标志牌。

A.通用泵

B.消防泵

C.国际通岸接头

D.固定式消防炮

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