The main thing is ____ (learn) how to be polite.

“枯藤老树昏鸦。小桥流水人家。古道西风瘦马。夕阳西下，断肠人在天涯。”该材料出自的文学作品的体裁是

阅读下面一首宋诗，然后回答问题。
                                                                                                       江上
                                                                                                    宋 王安石
                                                                                    江北秋阴一半开，晚云含雨却低徊。
                                                                                     青山缭绕疑无路，忽见千帆隐映来。