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【单选题】
I have lost one of my gloves. I ________ it somewhere. [ ]A.
must drop
B.
must have dropped
C.
must be dropping
D.
must have been dropped
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皮皮学刷刷变学霸
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【单选题】使同磁极下的导体边流过的电流方向不变,导体受力方向不变,进而产生方向恒定的电磁转矩,使电机连续转动,是下列哪个部件的作用( )。
A.
电刷
B.
电枢绕组
C.
换向器
【单选题】使同磁极下的导体边流过的电流方向不变,导体受力方向不变,进而产生方向恒定的电磁转矩,使电机连续转动,是下列哪个部件的作用( )。
A.
电刷
B.
电枢绕组
C.
换向器
D.
励磁绕组
【单选题】The development of the light bulb __ partly as a result of the widespread availability of electricity and the need for cheap, cicada light.
A.
occurring
B.
was occurring
C.
was occurred
D.
occurred
【单选题】The light bulb ______ by Edison in the middle of the 1780s.
A.
is invented
B.
was invented
C.
invented
D.
invent
【单选题】使同磁极下的导体边流过的电流方向不变,导体受力方向不变,进面产生方向恒定的电磁转矩,使电机连续转动,是下列哪个部件的作用()。
A.
电刷
B.
电枢绕组
C.
换向器
D.
永久磁铁
【单选题】使同磁极下的导体边流过的电流方向不变,导体受力方向不变,进面产生方向恒定的电磁转矩,使电机连续转动,是下列哪个部件的作用( )。
A.
电刷
B.
电枢绕组
C.
换向器
【简答题】Edison invented the light bulb many years ago（改为被动语态） The light bulb__________ __________by Edison many years ago．
【单选题】With a standard bulb, only 5% of the electricity is ______to light—the rest is wasted away as heat.
A.
compressed
B.
conformed
C.
converted
D.
confined
【简答题】灯泡 light bulb
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