睡眠监护系统软件是（）
A.第一类医疗器械
B.第二类医疗器械
C.第三类医疗器械
D.特殊用途医疗器械
参考答案：B
— Gorge and Lucy got married last week. Did you go to their wedding?
— No, I ______. Did they have a big wedding? [ ]
A. was not invited
B. hadn't been invited
C. have not been invited
D. didn't invite
在较大体积的混凝土墩台及其基础施工时，在混凝土中埋放石块的数量不宜超过混凝土结构体积的（）。
A．20%
B．25%
C．45%
D．50%
