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问题 多项选择题

变压器带点滤油时，应该注意（）。

A.遵守现在安全要求，确保滤油时的安全

B.所使用的设备外壳应有良好的接地

C.应将变压器的气体继电器退出跳闸回路，改接信号回路

D.注意选择充油设备又的进出口位置，防止油流死角和将沉淀物冲起

E.要控制油的流速，防止油流带电

答案

参考答案：A, B, C, D, E

多项选择题

直导体中产生感生电流的条件是（）。

A、直导体相对磁场作切割磁力线运动

B、直导体中磁通发生变化

C、直导体是闭合电路的一部分

D、直导体所在电路可以断开也可以闭合
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单项选择题

The kernel is the (66) of an operating system such as Windows98, Windows NT, Mac OS or Unix. The kernel provides basic services for the other parts of the operating system, (67) it possible for it to run several programs at once (multitasking), read and write files and connect to networks and peripherals. Applications and utility programs use the services provided by the kernel to provide practical business functionality.

In operating systems such as Windows or most versions of Unix, the kernel (68) everything except application and utility programs.

In microkernel operating systems such as Digital Unix and Apples forthcoming Mac OS Server, the kernel (69) supports only multitasking and memory management. Other services such as applications, utilities and the user interface support device drivers, API and graphics which all (70) outside the microkernel.

（70）处填（）。

A．live

B．dwell

C．occupy

D．reside
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