计算$\left(x^2+y\right)$$÷$$\frac{x^2+y}{x}$$·$$\frac{x}{x^2+y}$的结果是（　　）

一太阳能电池板，测得它的开路电压(电动势)为$800mV$，短路电流为$40mA$，若将该电池板与一阻值为60Ω的电阻器连成一闭合电路，则它的路端电压是(　　)

欧洲人酷爱乳产品和牛羊肉，其饮食结构与下列何种因素有着密切的关系 （ ）

    Do you know Chen Yixun? He is a great singer from Hong Kong. He has a lot of beautiful songs, so many people love him. This year Chen Yixun gives concerts (演唱会) in some cities in China. And on November 7 the concert is in Jiaxing.

    Chen Yixun wants to give great concerts, and he does a lot of work for that. First, he practises singing every day. And he always drinks warm water. There are also dances at the concerts, so he needs to practice dancing, too. It's a hard job. Then, he also needs to do exercise like running and swimming. He has to be healthy and strong for the concerts.

    “I have a busy life, but I love it. I enjoy singing and I wish to give great shows to people,” says Chen Yixun. Wish him good luck!