电视节目中我们看到“特斯拉线圈”表演，表演者通过有关设备造出人工闪电，放出美妙的电火花．以下说法错误的是（ ）
A．表演者与“特斯拉线圈”构成了闭合回路
B．表演者是在安全电压状态下演出的
C．表演者的防护服里有金属丝，电流只是经过金属丝
D．表演时发生了电能向光能、热能的转化
A、表演者与“特斯拉线圈”构成了闭合回路，才有电流产生；故A不符题意；
B、特斯拉线圈的原理是使用变压器使普通电压升压，然后经由两极线圈，从放电终端放电的设备．故表演者不是在安全电压状态下演出的；故B符合题意；
C、不能让此电流通过人体，对人体造成伤害；故表演者的防护服里有金属丝，电流只是经过金属丝；故C不符题意；
D、表演时，消耗了电能，获得了光能和热能；即发生了电能向光能、热能的转化；故D不符题意；
故选B．
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| In front of my daughter Sindu, was a bowl filled with cabbage. She hated cabbage. She only sat there in silence with tears __1__ her eyes. "Sindu, darling, why don't you __2__ a little? Your mom will shout at me." Sindu wiped (擦) her __3__ with the back of her hand. "OK, Dad. I'll eat, just a little." Then Sindu said, "Dad, if I eat it all, will you give me __4__ I want ?" "Yes, within reason." __5__ she began to eat. It took her almost half an hour to finish the __6__. Then she came up and said: "Dad, I want to have my head shaved (刮、剃) !" She said. "Sindu, why don't you __7__ something else? If we see you __8__," I said. "But, Dad, you promised! Now, you are going back on your words." I had to __9__ my promise. Sindu had all her hair cut off. She looked beautiful. On Monday morning, I took her to school. __10__ when we arrived, a boy got out of a car, and shouted," Sindu, please wait for me!" Guess what? The boy had __11__ hair ,either. "Sir, your daughter is __12__!" a man got out the car and said. "That boy is my son Harish. He has cancer. He lost his hair __13__ he got ill. Sindu cut hers off so Harish felt less __14__. She's a sepecial girl." I stood for a while, "My little girl, you __15__ me how selfless (无私的) real love is!" | |||
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