已知，⊙0的半径为2cm，0P=4cm，则过点P的⊙O的切线长为 ______m．

仔细观察下面的漫画，按要求答题。

 (1) 用简要的语言介绍这幅漫画的内容。

                                                                                                                                                            。 (2) 仔细观察这幅漫画，说说它反映了怎样的社会现象。

                                                                                                                                                            。