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问题 单项选择题

导致超声波穿透越深的条件是

A．超声波的反射强
B．组织介质密度低
C．组织介质的声阻大
D．超声波的能量吸收少
E．交界面两边介质声阻差别大

答案

参考答案：D

解析：超声波在介质中被吸收能量越小，穿透能力越强。

单项选择题

根据《中华人民共和国刑法》，未经国家有关主管部门批准，擅自发行股票或者公司、企业债券，数额巨大、后果严重或者有其他严重情节的，（）。

A.管制

B.处五年以下有期徒刑或者拘役，并处或者单处非法募集资金金额百分之一以上百分之五以下罚金

C.无期徒刑

D.死刑
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填空题

Press Photographers


Good press photographers must have an "eye" for news, (26) journalists must have a "nose" for a good story. They must be able to interpret a story and decide rapidly how they can take (27) of the best opportunities to take pictures. The most difficult part of a press photographer’s job is that he or she has to be able to (28) a complicated situation with just one photograph. They rarely have second (29) and must be able to take the required (30) very quickly. Indeed, speed is essential — if the photographs are not (31) for the printing deadline, they are very unlikely to be of any (32) .
Most press photographers begin (33) with a local newspaper. There, the (34) is mostly for material of regional interest. Photographers may be expected to photograph a lot of unexciting events but to (35) the enthusiasm to put "something special" into every picture.
There is (36) competition among those who want to move from local to national newspapers. Here, the work is much more centered on news. The photographer must work (37) greater pressure and (38) more responsibility. Only (39) reliable, talented and resourceful photographers (40) this difficult move. The work is tough and can be (41) . On an overseas assignment, photographers may have to (42) unfamiliar food and accommodation, physical and mental stress, and (43) difficulty in transporting the pictures from an isolated area to get them to the newspaper (44) They also have to (45) the competition from other publications.

A. essentialB. availableC. varied D. dangerous
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