单项选择题

电力系统在下列哪个条件下才能保证运行的稳定性，维持电网频率、电压的正常水平？（ ）

A.应有足够的静态稳定储备和有功、无功备用容量、应有合理的电网结构
B.应有足够的动态稳定储备和无功补偿容量，电网结构应合理
C.应有足够的储备容量，主网线路应装设两套全线快速保护
D.电网结构应可靠，潮流分布应合理
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单项选择题
发电厂人工接地装置的导体，应符合热稳定与均压的要求外，下面列出的按机械强度要求的导体的最小尺寸中，哪项是不符合要求的？（ ）
A.地下埋设的圆钢直径8mm
B.地下埋设的扁钢截面48mm2
C.地下埋设的角钢厚度4mm
D.地下埋设的钢管管壁厚度3.5mm
未分类题
Section A Dialogue CompletionDirections: In this section, you will read 5 short incomplete dialogues between two speakers, each followed by four choices marked A, B, C, and D.Choose the answer that best suits the situation to complete the dialoguE.Mark your answer on the ANSWER SHEET with a single line through the center.Speaker A: I need to make a hotel reservation for my father. Speaker B:______A.Why does your father want to stay in a hotel?B.Is your father going abroad?C.But do you know how to make a reservation?D.How about calling the travel agency?
A.Speaker
B.Why
C.Is
D.But
E.How
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