磁性开关中的干簧管是利用（）来控制的一种开关元件。
A、电流信号
B、温度信号
C、磁场信号
D、压力信号
参考答案：C
短文改错/Proofreading and error correction
It was the chance of a lifetime to win the first prize on the Story Writing Show. All I had to do was to write a story or present it. My teachers have been telling me how great my writing was. So if they had said was true, I would have a chance of winning the prize. What were better, I had useful help. There was Uncle Chen, gentleman living near my house, who was a very much famous writer. He agreed to reading my story and give me some advices on how to write like a real writer.
5（）
下列属于变形缝的是（）
A、施工缝
B、膨胀缝
C、伸缩缝
D、沉降缝
