根据下列条件求圆的方程：

用如图的实验装置探究烧杯内的某种物质熔化时温度的变化规律（烧杯内物质在相同时间内吸收的热量相同）

如图是某课外活动小组设计的小台灯电路图．S为单刀双掷开关，电源电压为12V．且保持不变．小灯泡的额定功率是6W，电阻R的阻值为6Ω．当开关S接“2”时，

小灯泡恰好正常发光．若灯丝电阻不变，试求：

英法两国在资产阶级革命后，分别建立了不同的资本主义国家政体。造成这种不同的原因，从政治文化传统方面说是由于(    )

阅读短文，从每小题所给的四个选项中，选出正确的选项。C
    Prana was my close friend, whose name means "bright boy in life." Although he died several years ago, I can still remember the days we spent together and what he taught me about love.
    I have two apple trees in the garden. Prana loved apples. When he went outside, he'd catch an apple and take it into the house to eat later. The apples had been on the ground and were often dirty so I wasn't always happy that Prana had brought them into the house.
    It was an autumn day in Britain, but it was very cold. A big snow fell and we had not done anything for its coming. On that special day, Prana went outside and I watched him through the window. I noticed that he was madly digging holes and bringing the apples to the ground so they could be seen above the snow. I did not know why he was doing this. It seemed that he wanted to do something special.
    When I called him back, he had his usual one apple in his mouth. About five minutes later, I looked outside. The garden was covered with birds. Prana had dug up all those apples for his birds' friends to eat. He knew that they wouldn't have stored enough food for the coming winter! It is just a dog who did such a great thing.