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【多选题】
霍尔传感器应用广泛,在通信领域,可以用于( )。A.
放大器
B.
振荡器
C.
混频
D.
分频
拍照语音搜题，微信中搜索"皮皮学"使用
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皮皮学刷刷变学霸
举一反三
【单选题】. They did everything they could to prevent the pollution ______ the river.
A.
protecting
B.
to protect
C.
from being protected
D.
from protecting
【单选题】If more short journeys were made by bicycles, energy could be saved and pollution ______.
A.
declined
B.
reduced
C.
dropped
D.
decreased
【简答题】主人公( )是骑自行车时被( )撞死的。
【单选题】It remains doubtful ______ immediate measures could be taken to prevent underground water pollution.
A.
how
B.
whether
C.
that
D.
where
【简答题】主人公 ( ) 是骑 自行车时被 ( ) 撞死的。
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