烟花爆竹经营许可证有效期为（）年。
A、4年
B、5年
C、6年
D、2年
参考答案：D
_________ much I dislike the idea of begging in the street, we should still show consideration for those who are in difficult situations.
A．However
B．How
C．Whatever
D．No matter
改良耕性，使作物根系穿插伸展顺利
