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【单选题】
可控整流电路和直流斩波电路，都是把电能的形式变换为直流电能。但是，二者主要特点的不同之处在于（）。A.
采用的变压器不同，前者采用工频变压器，后者采用高频变压器，后者体积更小
B.
采用的滤波器体积不同，后者滤波元件的尺寸更小
C.
采用的开关器件的类型不同，后者采用器件，可控性更好
D.
采用的工作频率不同，后者更高，电压动态响应更好
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皮皮学刷刷变学霸
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【简答题】朋友帮了他很多忙,他欠他们的情
【简答题】The Home Secretary described the latest crime figures as 'd__________'.(adj. 烦扰的)
【判断题】The British Home Secretary claimed that it would be impossible to protect civil liberties effectively when a terror attack was inevitable.
A.
正确
B.
错误
【单选题】It was ______ the president's speech that the secretary spent the whole morning at home.
A.
to prepare
B.
preparing
C.
prepared
D.
be prepared
【单选题】The Home Secretary________ it absolutely clear that he remains committed to meeting our obligation to genuine refugees.
A.
makes
B.
has been making
C.
has made
D.
made
【简答题】Priti Patel, Britain's home secretary, came under following the resignation of the most senior in her department.
【单选题】不引起呼吸道感染的一组病毒是
A.
冠状病毒、脊髓灰质炎病毒
B.
风疹病毒、乙型肝炎病毒
C.
人类免疫缺陷病毒、轮状病毒
D.
麻疹病毒、ECHO病毒
E.
腮腺炎病毒、柯萨奇病毒
【简答题】英语句子结构分析: The Home Secretary last night vowed to end EU free movement completely.
【单选题】不引起呼吸道感染的一组病毒是
A.
麻疹病毒、ECHO病毒
B.
风疹病毒、EB病毒、腺病毒
C.
冠状病毒、柯萨奇病毒
D.
呼肠病毒、腮腺炎病毒
E.
流行性乙型脑炎、轮状病毒
【单选题】The Home Secretary it absolutely clear that he remains committed to meeting out obligation to genuine refugees.
A.
makes
B.
has been making
C.
has made
D.
made
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