光发射机中实现电/光转换的关键器件是()

6.The biosphere is the name biologists give to the sort of skin on the surface of this planet that is inhabitable by living organisms. Most land creatures occupy only the interface between the atmosphere and the land;birds extend their range for a few hundred feet into the atmosphere;burrowing invertebrates(无脊椎动物)such as earthworms may reach a few yards into the soil but rarely penetrate farther unless.it has been recently disturbed by men. Fish cover a wider range,from just beneath the surface of the sea to those depths of greater than a mile inhabited by specialized creatures. Fungi(真菌)and bacteria are plentiful in the atmosphere to a height of about half a mile,blown there by winds from the lower air. Balloon exploration of the stratosphere(同温层)as long ago as 1936 indicated that moulds and bacteria could be found at heights of several miles,recently the USAs National Aeronautics and Space Administration has detected them,in decreasing numbers,at heights up to eighteen miles. They arc pretty sparse at such levels, about one for every two thousand cubic feet, compared with 50 to 100 per cubic foot at two to six miles(the usual altitude of jet aircraft),and they are almost certainly in an inactive state. Marine bacteria have been detected at the bottom of the deep Pacific trench,sometimes as deep as seven miles; they are certainly not inactive. Living microbes have also been obtained on land from cores of rock drilled(while prospecting for oil)at depths of as much as 1,200 feet. Thus we can say, disregarding the exploits of astronauts, that the biosphere has a maximum thickness of about twenty-five miles. Active living processes occur only within a compass of about seven miles,in the sea, on land and in the lower atmosphere, but the majority of living creatures live within a zone of a hundred feet or so. If this planet were sealed down to the size of an orange,the biosphere,at its extreme width,would occupy the thickness of the orange-colored skin,excluding the pith. In this tiny zone of our planet takes place the multitude of chemical and biological activities that we call life. The way in which living creatures interact with each other, depend on each other or compete with each other, has fascinated thinkers since the beginning of recorded history. Living things exist in a fine balance which is often taken for granted, from a practical point of view, things could not be otherwise. Yet it is a source of continual amazement to scientists because of its intricacy and delicacy. The balance of nature is obvious most often when it is disturbed. Yet even here it can seem remarkable how quickly it readjusts itself to a new balance after a disturbance. The science of ecology—the study of the interaction of organisms with their environment—has grown up to deal with the minutiae of the balance of nature.
According to the passage,the'biosphere'is the layer on the earths surface_____.
A．where the atmosphere meets the sea
B．in which birds, fish and animals would die
C．in which plant and animal life can exist
D．in which earthworms and other invertebrates can live此题为多项选择题。

A.it
B.
According
C.
A．where
D.in
E.in
F.in

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7.Many instructors believe that an informal, relaxed classroom environment is【C1】______to learning and innovation. It is not uncommon for students to have【C2】______and friendly relationships with their professors. The【C3】______professor is not necessarily a poor one and is still【C4】______by students. Although students may be in a(n) 【C5】______position,some professors treat them as【C6】______. However, no mat-ter how【C7】______professors would like to be,they still are in a position of【C8】______. Professors may【C9】______social relationships with students outside of the classroom, but in the classroom they【C10】______the instructors role. A professor may have coffee one day with students【C11】______the next day expect them to【C12】______a deadline for the【C13】______of a paper or to be pre-pared【C14】______a discussion or an exam. The professor may give【C15】______attention outside of class to a student in【C16】______of help but probably will not treat him or her differently when it【C17】______evaluating school work. Professors have several roles【C18】______students;they may be counselors and friends as well as teachers. Students must 【C19】______that when a teacher s role changes, they must appropriately【C20】______their behavior. and attitudes.
【C1】
A．instructive
B．conducive
C．constructive
D．healthy

A.
【C1】
A．instructive
B．conducive
C．constructive
D．healthy

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8.单项选择题传播沟通不仅包括信息()、()、()分享一系列过程，还包括信息的收集与处理，并且综合地运用各种传播方式和传播媒介。

A.传递、传播、接受
B.交流、传输、传达
C.传递、接受、交流
D.传达、接受、交流

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9.单项选择题根据一定的目的，运用已知信息，产生出某种新颖、独特、有社会或个人价值的产品的能力称为()。

A.回忆
B.思维
C.想象
D.创造力

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10.单项选择题在以下关于ieee802.5标准的讨论中，哪个论述是正确的()
A.TokenRing环中允许有多个令牌
B.令牌环网中结点连接到物理的环形通道中。
C.令牌总线是沿着物理环两个方向传送
D.令牌环控制方式具有与令牌总线方式相似的特点，如环中结点访问延迟确定，适用于重复载环境，支持优先级服务

A.5标准的讨论中，哪个论述是正确的()
A.TokenRing环中允许有多个令牌
B.令牌环网中结点连接到物理的环形通道中。
C.令牌总线是沿着物理环两个方向传送
D.令牌环控制方式具有与令牌总线方式相似的特点，如环中结点访问延迟确定，适用于重复载环境，支持优先级服务

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