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【单选题】
判断下列关于谐波的描述哪一项是错误的?请说明依据和理由。( )
A.
谐波可能在公用电网中产生并联谐振引起过电压而损坏电网中的其他用电设备
B.
谐波使接在统一电网中的电力电容器可能由于对谐波电流的放大而过电流
C.
并联电容器的阻抗特性,以及阻抗和频率成反比的特性,使得电容器容易吸收谐波电流而引起过载发热
D.
谐波电压与基波电压峰值不会发生叠加,电容器介质不会发生局部放电
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【单选题】Which sentence is right?
A.
Although she knew that it was dangerous, but she walked home by herself.
B.
My knee started hurting, I stopped running.
C.
Since we've got a few minutes to wait for the train, let's have a cup of coffee.
D.
She bought the whole lot-house and farm and horses and all.
【简答题】根据所给单词及括号内的汉语提示补全下面句子(每空一词)。 gather 1. Everyone in the gym stopped working out and ( 聚集在电视周围 ). 2. At this time of year , farmers are ( 收获庄稼 ) that they have grown. 3. The bicycle ( 加快了速度 ) as it went...
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A.
SET
B.
SSL
C.
CHAP
D.
SMTP
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A.
2分
B.
3分
C.
4分
D.
5分
E.
6分
【简答题】III.根据SectionA-3a短文, 用括号内所给动词的适当形式填空 (一)The bus driver Wang Ping saw an old man 1. ___________(lie)on the side of the road when bus No. 26 was going along Zhonghua Road. He stopped the bus without2....
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【单选题】在一定的范围内,随着产量的增加,总固定成本
A.
保持不变
B.
不断上升
C.
先下降后上升
D.
先上升后下降
【多选题】与物质生产部门相比,旅游产业具有( )等特点。
A.
生产与消费的同一性
B.
旅游产业的敏感性
C.
生产的稳定性
D.
生产的非物质化
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