谢亭送别
                                                                                                       许浑
                                                                              劳歌一曲解行舟，红叶青山水急流。
                                                                              日暮酒醒人已远，满天风雨下西楼。
                                                                              【注】①劳歌：送别歌。

所有三角形的内角和都是180°。（    ）

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

已知命题$p:\exists x\in R,x>\sin x$，则$p$的否定形式为（   ）

小红同学在做“探究平面镜成像”的实验时．将一块玻璃板竖直架在水平台上．再取两段完全相同的蜡烛A和B．点燃玻璃板前的蜡烛A．进行观察，如图所示．在此实验中：