阅读下面一首词，完成小题
                                                                               龟虽寿    曹操
                                                         神龟虽寿，犹有竟时。螣蛇乘雾，终为土灰。
                                                         老骥伏枥，志在千里；烈士暮年，壮心不已。
                                                         盈缩之期，不但在天；养怡之福，可得永年。
                                                         幸甚至哉，歌以咏志。