问题
多选题
| 如图为理想变压器原线圈所接交流电压的波形．原、副线圈匝数比n1：n2=10：1，串联在原线圈电路中电流表的示数为1A，下列说法正确的是（ ） A．变压器输出端所接电压表的示数为20 B．变压器的输出功率为200W C．变压器输出端的交流电的频率为50Hz D．穿过变压器铁芯的磁通量变化率的最大值为20  |
V
/n2Wb/s
答案
BCD
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| 如图为理想变压器原线圈所接交流电压的波形．原、副线圈匝数比n1：n2=10：1，串联在原线圈电路中电流表的示数为1A，下列说法正确的是（ ） A．变压器输出端所接电压表的示数为20 B．变压器的输出功率为200W C．变压器输出端的交流电的频率为50Hz D．穿过变压器铁芯的磁通量变化率的最大值为20 |
BCD
| 完形填空 | ||||
| I can still remember when I met my best friend. She had just moved into the neighborhood and her grandmother brought her down to 1 me. I hid behind my mother and she hid behind her grandmother, 2 to look at each other. Soon we lost the 3 and started playing with each other. In the 7th grade, I first lost touch with her. She was 4 family problems and I deserted her to be with the 5 people. None of my new friends liked her as much as I did because they knew she had 6 . However, every summer we 7 always sit at each other's house, watch soap operas, and talk about all the boys we liked. It was last year when I noticed the problem. I guess I was 8 devoted in high school to 9 she needed someone there. Anyway, she made a new best friend and so did I. Then I didn't know why, 10 she started cutting herself! She then was diagnosed(诊断)with clinical depression. At first, I was very 11 , but we still stayed in 12 I wanted to be there with her since her new best friend basically 13 her and people were calling her 14 . Yesterday she came to me and said, "I never knew what a best friend was 15 you, the only person, would stop me cutting. I 16 your help so much, and you didn't even know you were 17 me." We both cried. And I guess a kind of 18 from my life so far is never to give up on your friends. Even if they aren't as cool as others, or people think they are crazy, they need 19 there. If you desert them, you will only be 20 yourself. | ||||
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