如图所示是光电管使用的原理图．当频率为ｖ的可见光照射到阴极Ｋ上时，电流表中有电流通过，则                                                （   ）

在下列诸侯国中，既属“春秋五霸”，又是“战国七雄”之一的是（  ）

“群众是一串‘零’，再多也是零;杰出人物则是这串‘零’前的非零实数，一加到零前，就成了一个天文数字。”此观点(   )

漫画说明(　　)

①全球环境问题是全人类共同面临的环境问题　②如何共同应对全球环境问题带来的挑战，已成为人类面临的一项重大课题　③解决全球环境问题，要坚持共同但又有差别的义务的原则　④全球环境问题，危及人类的生存与发展

Dear Grace,
    How are you? Thank you for your last e-mail. You want to know about my school clubs, right ? Well, it's time for us to join the school clubs now. There are many clubs in my school, like the English club, the art club, the music club and the sports club. I have two good friends, Jack and Lisa. We all want to join the school clubs.
    I want to join the music club, because I can play the guitar. I can't speak English well, but I also want to join the English club.
Jack likes sports. He can play soccer and basketball. He is in the school soccer team(队). He wants to join the sports club. He can play the guitar, too. But he doesn't want to join the music club.
    Lisa likes drawing. She wants to join the art club. She also speaks English very well. I think she can be in the English club. But she can't be in the music club. She can't play any instruments(乐器).
    Are there any clubs in your school? What club are you in? Please write an e—mail and tell me about your school clubs.
Yours,
Jane