单项选择题
A.Ns Sc As St B.Sc As Cs Fs C.Ci Cs As Ns D.Fs Ns As St
A.Cu TCu Cb Fc B.TCu Fc Cc Sc C.Cb Sc Ac Cu D.Fc Cu Cb Cc
A.对流 B.系统性上升运动 C.波动 D.乱流