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问题 单项选择题

在SMPS700整流模块中的主要工作单元的功能中，下列说法错误的是（）

A.预调板的功能是将输入交流电变成稳定的高压直流电

B.DC/DC变换器的作用是将高压直流电变成稳定的低压直流电

C.包含预调板和DC/DC变换器，采用零电流开关准移谐振技术

D.工作在热插拔状态，开机和带负载是可以插拔

答案

参考答案：C

单项选择题

These days, everyone talks about being too busy. But all this busyness does not seem to result in things getting done. Just as many tasks are still left uncompleted, phone calls unreturned, and appointments missed as there were in the days before this outbreak of busyness. Therefore, people must not be as busy as they claim.
Which one of the following, if true, would most seriously weaken the conclusion in the passage

A．These days, looking busy is a status symbol.

B．People have to do much more these days than before the so-called outbreak of busyness.

C．People waste so much time talking about being busy that they fail to get things done.

D．Just as many things are getting done now as before the so-called outbreak of busyness.

E．(E) People have more leisure time these days than before the so-called outbreak of busyness.
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判断题

根据种子质量可将种子分为育种家种子，原原种，原种。
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