胸部高电压摄影，滤线栅的栅比不应小于（） A.8：1 B.10：1 C.12：1 D

为培育和践行社会主义核心价值观，江苏省从2014年春季学期开始在全省未成年人中开展“八礼四仪”的文明礼仪养成教育。“八礼”中的第一礼“仪表之礼”，要求未成年人做到面容整洁、衣着得体、发型自然、仪态大方。“仪表之礼”告诉我们

A．懂礼节、有礼貌，才是有教养的人

B．要注意生活细节，做有教养的人

C．有良好的仪表就是有教养的现代人

D．教养是通过学习和锻炼得以提升的

将健康问题提到各级各部门的议事日程上，促进健康公共政策的多样互补，使之了解其决策对健康的影响并承担健康责任，属于健康促进领域中的

A．创造支持环境

B．制定促进健康的公共政策

C．调整卫生服务方向

D．加强社区行动

E．发展个人技能

下列哪项不属于心脏骤停的诊断要点

A．意识突然消失，呼之不应

B．大动脉搏动消失

C．血压突然升高，心律不齐

D．自主呼吸停止

E．瞳孔散大，对光反射消失

对于电信公司和商场的行为，说法正确的是：( )。

A．电信公司指定购买电话机的行为是滥用合法的独占地位限制竞争的行为

B．电信公司指定购买电话机的行为是搭售及附加不合理条件的行为

C．商场给电信公司折扣的行为是商业贿赂行为

D．商场给电信公司折扣的行为是低价倾销行为

The marvelous telephone and television network that has now enmeshed the whole world, making all men neighbors, cannot be extended into space. It will never be possible to converse with anyone on another planet. Even with today’s radio equipment, the messages will take minutes—sometimes hours—on their journey, because radio and light waves travel at the same limited speed of 186, 000 miles a second.

Twenty years from now you will be able to listen to a friend on Mars, but the words you hear will have left his mouth at least three minutes earlier, and your reply will take a corresponding time to reach him. In such circumstances, an exchange of verbal messages is possible—but not a conversation.

To a culture which has come to take instantaneous communication for granted, as part of the very structure of civilized life, this "time barrier" may have a profound psychological impact. It will be a perpetual reminder of universal laws and limitations against which not all our technology can ever prevail. For it seems as certain as anything can be that no signal--still less any material object—can ever travel faster than light.

The velocity of light is the ultimate speed limit, being part of the very, structure of space and time. Within the narrow confines of the solar system, it will not handicap us too severely. At the worst, these will amount to twenty hours—the time it takes a radio signal to span the orbit of Pluto, the outer-most planet.

It is when we move out beyond the confines of the solar system that we come face to face with an altogether new order of cosmic reality. Even today, many otherwise educated men—like those savages who can count to three but lump together all numbers beyond four—cannot grasp the profound distinction between solar and stellar space. The first is the space enclosing our neighboring worlds, the planets; the second is that which embraces those distant suns, the stars, and it is literally millions of times greater. There is no such abrupt change of scale in the terrestrial affairs.

Many conservative scientists, appalled by these cosmic gulfs, have denied that they can ever be crossed. Some people never learn ; those who sixty years ago scoffed at the possibility of flight, and ten years ago laughed at the idea of travel to the planets, are now quite sure that the stars will always be beyond our reach. And again they are wrong, for they have failed to grasp the great lesson of our age— that if something is possible in theory, and no fundamental scientific laws oppose its realization, then sooner or later it will be achieved.

One day we shall discover a really efficient means of propelling our space vehicles. Every technical device is always developed to its limit and the ultimate speed for spaceships is the velocity of light. They will never reach that goal, but they will get very near it. And then the nearest star will be less than five years voyaging from the earth.

Conservative scientists who deny that cosmic gulfs can ever be crossed will（）

A. laugh at the very idea of flight

B. learn a lesson as they did ten years ago

C. find space travel beyond their reach

D. oppose the fundamental scientific laws