圆柱和圆锥的侧面都是请选择CBA0T*i)k'M0n'L8t4W(w5T-p'e9J9h
A.平面'L8t4W(w5T-p'e9J9h
B.曲面'L8t4W(w5T-p'e9J9h
C.直面'L8t4W(w5T-p'e9J9h