单项选择题
A.The persence of cirrus clouds B.The low-hanging stratus clouds C.The altocumulus clouds D.The massive cumulus clouds
（）may be a warning for an approaching storm.A.The perse...
单项选择题（）may be a warning for an approaching storm.
Nimbus means（）.A.rainB.highC.layerD.cirrus
单项选择题Nimbus means（）.
A.rain B.high C.layer D.cirrus
Alto stands for（）.A.rainB.highC.layerD.cirrus
单项选择题Alto stands for（）.
