题干

某三挡电炖锅的工作电路可简化为如图所示的电路图,其两段电热丝的阻值分别为R1和R2,且R1>R2,说明书的部分参数如表.


额定电压

电炖锅挡位

额定功率

220V

低温

200W

中温

400W

高温

600W


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    There are many differences between country life and city life in many ways. One person even does different things in the two places.

    Julia lived in the countryside, but one year she decided to visit the capital city to do some shopping and to see the sights. She stayed at a hotel near the central market. She had seldom been to the city before, and was very excited about what she would find.

    On the first morning of her visit, as she walked from the hotel to the market, she passed a beggar(乞丐). He was holding up a notice, which said, “Blind from birth. Please give generously(慷慨地).”

    Julia felt sorry for the blind beggar and she bent down and put a dollar coin into his bowl. “Thank you.” he said.

    The same thing happened again the following day.

    On the third day, however, Julia did not have a dollar coin. She had only fifty cents, so she dropped this into the beggar's bowl.

    “What have I done wrong?” the beggar said, “Why are you so stingy today? ”

    Julia was very surprised at what the beggar said. “How do you know I haven't given you a dollar?” she said, “If you're blind you can't know what coin I put into your bowl.”

    “Ah, ” explained the beggar, “The truth is that I'm not blind. I'm just looking after this place for the regular beggar while he's on holiday.”

    “On holiday?” Julia said, “And what exactly does your blind friend do on holiday?”

    “He goes into the countryside,” the man said, “and takes photographs. He's a very good photographer.”