题目

下列表述不正确的是（ ） A．电话机的听筒里用到了声音传感器 B．电水壶的三角插头内装有熔断器 C．玩具电动机也可以用来发电，且“电机”输出的电流方向不变 D．电冰箱不宜放在使用煤气的厨房中   答案：A 【分析】 要解决此题，需要掌握电话机听筒和话筒的区别，安全用电的原则以及发电机与电动机的结构原理。 【详解】 A．电话机的听筒利用电流的磁效应原理工作，将电信号变成声音信号，没有应用传感器，故A错误，符合题意。 B．电水壶的三角插头内装有熔断器，故B正确，不符合题意； C．发电用括号内所给单词的适当形式填空。【1】As we know, Changjiang is the ________ (three) longest river in the world.【2】Uncle Sam is an old man with lots of________( hobby), like playing basketball and painting.【3】To keep healthy, we should eat________ (little) meat and more fruit and vegetables.【4】He needs money to buy a house so he wants to sell his car________ (cheap).【5】I didn’t finish ________ (write)my test because I ran out of time.