330、500kV级升压变压器高压侧的额定电压最好以下面( )原则来_爱下问搜题

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问题单项选择题

330、500kV级升压变压器高压侧的额定电压最好以下面( )原则来选择。

A．按1.15倍系统额定电压选择；
B．按1.10倍系统额定电压选择；
C．按1.05倍系统额定电压选择；
D．按系统无功功率分层(电压)平衡要求经计算论证后确定。
，

答案

参考答案：D

改错题

短文改错。

     One afternoon Mr. smith entered into my flower shop and
ordered some flowers for his wife. "Not card is necessary,"
he said, she would know who sent them." The deliver
hadn't even returned to the store while the phone rang.
It was Mr. smith's husband. "Who sent the flowers?"
she asked. After explained that the customer had required
that no card was included, I considered the matter had
come to a close. But not so. She came rush into my door.
"You're got to tell me who sent the flowers," he
demanded, "after my husband gets home for lunch!"

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单项选择题

在图示平面机构中，AB杆借助滑套B带动直角杆CDE运动，在图示位置，θ=30°，角速度ω=2rad/s，角加速度ε=1rad/s2，且知曲柄AB长L=10cm，则该瞬时D点的速度V和加速度a为（）。

A.10cm／s↑，20+5cm／s2↑

B.10cm／s↓，20+5cm／s2↑

C.10cm／s↑，20+5cm／s2↓

D.10cm／s↓，20+5cm／s2↓