问题
单项选择题
由泵的特性曲线可以看出离心泵启动前要关闭出口阀的原因是（）。
A.流量最小功率最小
B.功率最小扬程最高
C.效率最小扬程最高
D.功率最小效率最小
答案
参考答案：A
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由泵的特性曲线可以看出离心泵启动前要关闭出口阀的原因是（）。
A.流量最小功率最小
B.功率最小扬程最高
C.效率最小扬程最高
D.功率最小效率最小
参考答案：A
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| When I was a teenager I volunteered to work at the water station at a 10,000m race. My job was to 1 water to the runners. I remember being so 2 to see all the different kinds of people who passed by and grabbed a cup of water. Some ran past, some walked past and a few wheeled past. I saw so many types of people doing it. I thought maybe I could do it too! So the next year I 3 up for the race. That first 10,000m race was quite an 4 . I jogged, I walked, I jogged and I walked. 5 , I didn't know if I could finish. Then came a defining (决定性) 6 . At one point near the end, a 70-year-old man ran past me, very, very fast, and I felt 7 because I was 50 years younger than he but I couldn't even keep up with him. I felt 8 for a second. But then I 9 something. He was running his race and I was running mine. He had 10 abilities, experience, training and goals for himself. I had mine. Remember my 11 was only to finish. After a minute, it 12 me that this was a lesson I could draw from. I learned something about myself in that moment. I turned my embarrassment into 13 . I 14 that I would not give up on running races. In fact, I would run even more races and I would learn how to train and prepare 15 and one day I would be one of those 70-year-old persons who were still running. As I crossed the finish line, I was proud of my 16 . In life we all have those moments where we 17 ourselves to others. It's only 18 . Don't allow those moments to 19 you. Turn them into motivation and let them inspire you. With the proper preparation and training, you can improve your result to 20 anything you want in life. | ||||
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