先化简,再求值:xx+2+x2-2xx2-1÷(x-1-2x-1x+1),其中x

题型:解答题

问题:

先化简,再求值:
x
x+2
+
x2-2x
x2-1
÷(x-1-
2x-1
x+1
)
,其中x2+x-1=0.
考点:分式的加减乘除混合运算及分式的化简
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只接受公正、公平、合理的职业报酬,是()

A.执业药师的执业行为规范

B.执业药师的道德准则

C.执业药师的责任

D.执业药师的权力

E.执业药师的义务

题型:解答题

发爆器或起爆接线盒都必须采用矿用防爆型的(矿用增安型的除外)。()

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沈阳市于洪区主要领导表示:“我们要牢固树立抓环境就是抓发展,抓环境就是抓民生的思想意识!”这种说法[ ]

①体现了保护和改善环境是保护和发展生产力

②把环境保护同经济建设对立起来

③坚持了以经济建设为中心

④坚持了保护环境的基本国策

A.①②③

B.②③④

C.①③④

D.①②④

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Besides providing a perfect environment for sea plants and animals to live in, seawater has other values, one of which is that it constantly moves, and its movements produce energy.

The most obvious movements are the waves and the tides. Winds cause the waves, and the gravitational pull of the moon and the sun causes the tides. In places like the Bay of Fundy in Canada, the difference between the high and low tide level can be as much as 40 feet.

France and Britain are now trying to use energy in the tides to produce electricity. Waves can produce electricity and some experiments are taking place to learn more about this. One of the most encouraging areas of research uses the difference between the temperature of seawater at the surface and deep down to produce electricity. 

小题1:Waves and tides are caused by ________ .

A.the same forces

B.different forces

C.their own movements

D.plants and animals小题2:It can be inferred from the passage that __________ .

A.waves as well as the energy in the tide can produce electricity

B.the highest tide is 40 feet higher than the lowest one at the sea

C.many countries in the world have made the most of energy produced by seawater

D.it is being tried in some developed countries to use energy in the tides to produce electricity小题3: The best title for the passage is ______.

A.Tides and Waves

B.How to Produce Electricity

C.Seawater

D.Another Cheap Energy

题型:解答题

水平角测量时,角值β=b-a。现知读数a为60°25'12",读数b为187°47'36",则角值口是( )。

A.127°35'36"

B.127°38'48"

C.127°22'24"

D.127°33'12"

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