古诗鉴赏。

阅读下面这首古诗，完成小题。
                                                                                                    春行即兴  

                                                                                                             唐 李华
                                                                                   宜阳城下草萋萋，涧水东流复向西。
                                                                                   芳树无人花自落，春山一路鸟空啼。
                                                                                                     【注】本诗写于安史之乱平息后不久。

________ volunteers will give out leaflets to ask people to protect the wetlands.

已知倾斜角为θ的直线，与直线x﹣3y+1=0垂直，则tanθ=（　　）