问题
单项选择题
电源频率增加，变压器的（）减小。
A.原边电势
B.输出功率
C.励磁电流
D.铁心损耗
答案
参考答案：B
搜题请搜索小程序“爱下问搜题”
电源频率增加，变压器的（）减小。
A.原边电势
B.输出功率
C.励磁电流
D.铁心损耗
参考答案：B
| 阅读理解。 | |
| There is a book shop near our school. Its name is Hanlin Bookshop. There are all kinds of books in it. It is open from nine in the morning to seven in the evening. On Sundays it is open from nine to five. It is closed（关闭的）in winter holidays(寒假).Jim and his father often go to the shop. His father always goes to the second floor. He likes to buy science books. Jim likes the books for children on the first floor. They sometimes go to the third floor to buy some computer books and CDs. | |
根据短文的内容，完成下列的图表：
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