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【单选题】
某交流用电器的额定电压为220V、额定频率为50Hz,其两端加上下列哪种正弦电压,会保证其正常工作______。A.
–311sin314tV
B.
220sin314tV
C.
380sin314tV
D.
311sin50tV
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举一反三
【单选题】The meeting has been on for five hours and the plan of our activity is still____. [ ]
A.
uncertain
B.
known
C.
certain
D.
sure
【单选题】— The plan I put forward at the meeting has been _____. — That's great. [ ]
A.
approved
B.
mastered
C.
absorbed
D.
rejected
【单选题】The meeting has been postponed till next Friday.
A.
called off
B.
taken off
C.
put off
D.
pulled off
【简答题】The meeting has been called .
【单选题】How do you paraphrase the sentence "The meeting has been delayed."?
A.
Someone is delaying the meeting.
B.
Someone is putting off the meeting.
C.
The meeting was putted off.
D.
The meeting has been put off.
【简答题】The meeting has been put for a week.
【单选题】The date of the meeting has been from Friday to Monday.
A.
polluted
B.
owned
C.
mined
D.
advanced
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