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【简答题】
In electronicpower supplies there is often a need to isolate the output from the input andreduce the weight and cost of the unit. In other applications, such as inaircraft, there is a strong incentive to minimize weight. These objectives arebest achieved by using a relatively high frequency transformer. Thus, inaircraft the frequency of transformers is typically 400Hz, while in electronicpower supplies the frequency of transformers may range from 5kHz to 50kHz
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【单选题】关于妊娠合并淋菌感染的说法，下列哪项是不恰当的
A.
妊娠早期可致感染性流产
B.
易发生胎儿宫内感染
C.
对可疑感染者取分泌物培养可确诊
D.
治疗首选喹诺酮类药物
E.
淋病高发区孕妇产前常规筛查淋菌
【单选题】When making a comparision between the past and the present condition of a place , we might say ' It's gone to the dogs '. What does it mean ?
A.
It is in a much better condition now than it was before .
B.
It is in almost the same condition now as it was before .
C.
It is in a much worse condition now than it was before .
D.
There are many dogs here now , but there weren't brfore .
【简答题】Dogs can also go to school to learn how to help people who cannot hear. If a person cannot hear, we say he or she is deaf. Dogs who help deaf people must learn many different sounds. Then they must be...
【简答题】完形填空。 We see many animals, like rabbits, bees, dogs, birds, sheep but do you know 1 these animals say things? First, let's see a rabbit. When a rabbit sees something 2 , it runs away at once. When it ...
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