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问题 单项选择题

2号发动机的起动机是由什么来驱动的（）

A、气源系统的空气

B、G系统液压

C、Y系统液压

答案

参考答案：A

选择题

某温度下，水的离子积常数KW＝10－12。该温度下，将pH＝4的H2SO4溶液与pH＝9的NaOH溶液混合并保持恒温，欲使混合溶液的pH＝7，则稀硫酸与NaOH溶液的体积比为

A．1∶10

B．9∶1

C．10∶1

D．99∶21
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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. struggle for B. get by C. cope with D. stand up
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