次北固山下
                                                                                                王湾
                                                                                 客路青山外，行舟绿水前。
                                                                                 潮平两岸阔，风正一帆悬。
                                                                                 海日生残夜，江春入旧年。
                                                                                 乡书何处达？归雁洛阳边。

PA、PB切⊙O于A、B两点，CD切⊙O于点E，交PA、PB于C、D，若⊙O的半径为r，△PCD的周长等于3r，则tan∠APB的值是 ____

    Bob and Sue are in the same school，1they are in different classes.After school，Bob and Sue often play games with their friends.Class begins at eight in the morning.Now Bob and Sue are in2own classrooms.They are3to their teachers.Bob is studying English.Sue is having an art lesson.She4to make a birthday card5her mother.

    Her teacher Miss Li is helping her.