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问题 填空题

如果四冲程汽油机的活塞在气缸内往复运动四次，则燃气推动活塞做功______次，曲轴转动______周．若飞轮转速为1800转/分，则每秒钟汽油机完成______个工作循环，燃气推动活塞做功______次．

答案

在内燃机的一个工作循环中，曲轴转动2周，做功1次；

飞轮转速为1800转/分=30r/s，所以可以完成15个工作循环，做功15次；

故答案为：1，2，15，15．

单项选择题 A1型题

水俣病的发病原因是（）。

A.慢性砷中毒

B.慢性镉中毒

C.慢性铅中毒

D.慢性硒中毒

E.慢性汞中毒
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单项选择题

A client, age 59, complains of leg pain brought on by walking several blocks--a symptom that first arose several weeks ago. The client’s history includes diabetes mellitus and a two-pack-a-day cigarette habit for the past 42 years. The physician diagnoses intermittent claudication and prescribes pentoxifylline (Trental), 400 mg three times daily with meals. The nurse should provide which instruction concerning long-term care（）

A. "Practice meticulous foot care. "
B. "Consider cutting down on your smoking. "
C. "Reduce your level of exercise. "
D. "See the physician if complications occur. "
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