银杏属于裸子植物的原因是（　　）

别人请求的事情，应该尽量答应，至于能不能兑现则无关（   ） 

                                                                                                            兰溪棹歌^①
                                                                                                               戴叔伦
                                                                                     凉月如眉挂柳湾，越中山色镜中看。
                                                                                     兰溪三日桃花雨，半夜鲤鱼来上滩。
                                                              【注释】①兰溪，在今浙江兰西县西南。棹（zhào）歌：船歌。