A.保持不變 B.降 C.上升 D.下降1.5倍
A.需求數(shù)量上升10% B.需求數(shù)量下降10% C.需求數(shù)量上升90% D.需求數(shù)量下降90%
A.2 B.1 C.0 D.0.5