题目

Mr. Jenkins liked all kinds of delicious food. As an important officer, he was often asked to dinner. The shopkeepers tried their best to fawn on(巴结) him. They knew it was good for their business. Now the officer got fatter and fatter. He could hardly go upstairs（楼上） at home and had to sleep downstairs. He often felt tired if he walked or did some housework. He was worried about it and had to go to a doctor. “Stop eating much fat(脂肪) and sugar, Mr. Jenkins,” said the doctor, “or it will be worse for your health!” It was difficult for the officer to do it. He didn’t do打点计时器是利用______电源进行的______仪器，若电源频率为50HZ则它们每隔______秒打一个点，每5个间距对应的时间为______秒，其中电磁打点计时器所用电压为______伏，电火花打点计时器所用电压为______伏．