三级耐火等级的民用建筑物,最多允许层数是()层。
A.3
B.5
C.6
D.8
参考答案:B
I'm not sure which restaurant ______ because I haven't been here for long. [ ]
A. to be eating
B. to eat at
C. to eat
D. eating at
对椎间盘的描述,正确的是( )
A.成人共有23个
B.周围是由多层纤维软骨环组成
C.可缓冲外力对脊柱的震动
D.可增加脊柱的运动幅度
E.中胸部的椎间盘较厚