On coming into the kitchen, mother found the soiled (污染的) dishes piled _____. [ ]

A. at risk

B. at random

C. at length

D. at ease

有关麻醉用气体储存于压缩气筒内的物理状态，哪项是错误的（）

A.氧气呈压缩气状态

B.二氧化碳呈液化气状态

C.空气呈压缩气状态

D.环丙烷呈压缩气状态

E.氧化亚氮呈液化气状态