问题
单项选择题
交流测量表所指示的读数是正弦量的（）
A、最大值
B、平均值
C、有效值
答案
参考答案：C
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交流测量表所指示的读数是正弦量的（）
A、最大值
B、平均值
C、有效值
参考答案：C
I heard a story about a famous scientist who had made several very important achievements. What made him 41 from others? He said it all came from 42 that happened when he was two years old. He tried to 43 a bottle of milk away from the fridge, but the slippery(光滑的) bottle fell, spilling its milk all over the 44 floor. When his mother came in, 45 shouting at him, she said, “Robert, what a great mess(一团糟) you have made! I have never seen such a big puddle(水坑) of milk. Would you like to get down and play in the milk for a few minutes 46 we clean it up?” Indeed, he did. After a few minutes, his mother said, “Robert, when you make a mess like this, you have to clean it up at last. So, 47 would you like to do that? We would use a towel or a mop. Which do you prefer?” He chose the towel and together they cleaned up the milk. His mother then said, “We had a failed 48 in how to carry a big milk bottle with two small hands in the kitchen. Let’s go out and fill the bottle with water and see if you can 49 a way to carry it without dropping it.” The little boy learned that if he held the bottle at the top near the lip(杯口) with both hands, he could carry it without dropping it. This scientist then said that it was at that moment that he knew he didn’t need to be afraid to 50 .So, what have you learnt from the story?
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