上海和武汉相距925千米,两车同时从两地出发,相向而行,出发4小时正好行驶了全程

题型:解答题

问题:

上海和武汉相距925千米,两车同时从两地出发,相向而行,出发4小时正好行驶了全程的80%.已知从武汉开出的汽车每小时行驶90千米,问从上海开出的汽车每小时行驶多少千米?

考点:整数,小数,分数,百分数和比例的复合应用题
题型:解答题

Astronomy is the oldest science known to man. Thousands of years ago man looked at the stars and wondered about the heavens. But man was limited by what he could see with his eyes alone.

The Greeks studied astronomy over 2,000 years ago. They could see the size, color, and brightness of a star. They could see its place in the sky. They watched the stars move as the seasons changed. But the Greeks had no tools to help themselves study the heavens.

Each new tool added to the field of astronomy helped man reach out into space. They did not know that the planet called Saturn(土星) had rings around it. Their sight was so limited that they could not see all the planets. In the early 1700s, people thought there were only six planets. Nepture(海王星), the last of eight planets to be discovered, was not seen until 1846.

Before the spectroscope(分光镜), man did not know what kind of gases was in the sun or other stars. Without the radio telescope, we didn’t know that radio noises came from far out in space.

Today, astronomy is a growing science. We had learned more in the last fifty years than in the whole history of astronomy.

小题1:. Thousands of years ago, people observed the stars with the limitation of their _____.

A.eyesight

B.land

C.wealth

D.knowledge小题2:. When the Greeks watched the stars, they could ____ .

A.know what the stars were made of

B.not see their places in the sky

C.help themselves study the heavens

D.watch the stars move as the seasons changed小题3:. Until there were ____, man knew very little about the moon.

A.telescopes

B.spectroscopes

C.radio telescopes

D.spaceships小题4:. Which of the following sentences is NOT true?

A.Astronomy is the oldest science that humans have known.

B.Astronomy is developing fast with the help of technology.

C.In the early 1700s, people didn’t know the existence of Neptune.

D.Over 2,000 years ago, the Greeks knew the planet Saturn had rings around it.小题5:. This passage mainly talks about _____.

A.tools used in astronomy

B.the development of astronomy in the last 50 years

C.Greeks’ achievements in astronomy

D.new tools and the development of astronomy

题型:解答题

【选修2化学与技术】(15分)

由黄铜矿(主要成分是CuFeS2)炼制精铜的工艺流程示意图如下:

(1)在反射炉中,把铜精矿砂和石英砂混合加热到1000℃左右,黄铜矿与空气反应

生成Cu和Fe的低价硫化物,且部分Fe的硫化物转变为低价氧化物。该过程中两个主

要反应的化学方程式分别是                                                 、

                                              ,反射炉内生成炉渣的主要成分是                  

(2)冰铜(Cu2S和FeS互相熔合而成)含Cu量为20%--50%。转炉中,将冰铜加

熔剂(石英砂)在1200℃左右吹入空气进行吹炼。冰铜中的Cu2S被氧化为Cu2O,生成Cu2O与Cu2S反应,生成含Cu量约为98.5%的粗铜,该过程发生反应的化学方程式分别是                                   、                                    

(3)粗铜的电解精炼如右图所示。在粗铜的电解过程中,粗铜板应是图中电极_    _(填图中的字母);在电极d上发生的电极反应式为                         ;若粗铜中还含有Au、Ag、Fe,它们在电解槽中的存在形式和位置为                     

题型:解答题

       每年的三月是学                       ,树新风的时间,作为一代新人,我们要将他的精神世世代代传下去,时时、处处都要向他学习。 [ ]

A.王进喜

B.邓稼先

C.焦裕禄

D.雷锋

题型:解答题

液态水具有压缩性和膨胀性,通常状况下,二者的特性为()。

(A)压缩性小,膨胀性小 

(B)压缩性小,膨胀性大 

(C)压缩性大,膨胀性小 

(D)压缩性大,膨胀性大

题型:解答题

关于脑血肿,下列说法正确的是()

A.急性脑血肿(0~2天)血肿中心在T2加权像上出现低信号。 

B.亚急性初期(第3天)血肿外围T1加权像上出现高信号。 

C.亚急性中期(6~8天)血肿在T1加权像、T2加权像上均出现高信号。 

D.亚急性后期(10~14天)血肿周围在T2加权像上出现低信号环。 

E.以上均对。

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