两条直线被第三条所截,则 (     )

阅读下面古诗，按要求答题。
                                                                                                   饮  酒
                                                                                    结庐在人境，而无车马喧。
                                                                                    问君何能尔，心远地自偏。
                                                                                    采菊东篱下，悠然见南山。
                                                                                    山气日夕下，飞鸟相与还。
                                                                                    此中有真意，欲辨已忘言。