A.不斷下降 B.上下波動(dòng) C.不斷上升 D.相對(duì)穩(wěn)定
A.10%~30% B.15%~30% C.15%~20% D.10%~20%
A.最高點(diǎn) B.最低點(diǎn) C.中間點(diǎn) D.溢出點(diǎn)