在感应加热表面淬水中，通入中频或高频交流电迅速加热，几秒钟内

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问题单项选择题

在感应加热表面淬水中，通入中频或高频交流电迅速加热，几秒钟内可使表层温度上升至（）℃，而心部温度仍接近常温。

A.500-600

B.600-700

C.700-900

D.800-1000

答案

参考答案：D

选择题

Frederick William I, the King of Prussia, _____ that his greatest gift to the Russian people would have _____. [ ]

A. had never imagined; such an amazing history

B. had never imagined; so amazing history

C. could never have imagined; such an amazing history

D. could never have imagined; so amazing history

单项选择题

下列关于正常枕先露分娩机制顺序，正确的是

A．衔接→下降→俯屈→内旋转→仰伸→复位及外旋转
B．衔接→俯屈→下降→内旋转→仰伸→复位及外旋转
C．衔接→下降→内旋转→俯屈→仰伸→复位及外旋转
D．下降→俯屈→衔接→内旋转→仰伸→复位及外旋转
E．下降→衔接→俯屈→内旋转→仰伸→复位及外旋转