从生物在分类上的位置，可以了解生物间的______关系。
A．生存环境
B．亲缘
C．外形
D．习性
答案：B
— Listen! Is Rose singing in the next room?
— No. It ______ be Rose. She has gone to Shanghai. [ ]
A. may not
B. can't
C mustn't
D. needn't
风蚀作用
