按岩块的湿抗压与干抗压的比值判定岩石的软化性，其值应为：
A.0.90；
B.0.80；
C.0.75；
D.0.50；
参考答案：C
— Oh, that's just my missing pen. Where on earth was it?
— It _____ off the table into the corner. [ ]
A. has fallen
B. fell
C. falls
D. was falling
牡蛎散的功用是
A．镇惊安神
B．益气养阴
C．益阴潜阳
D．益气固表
E．固表敛汗
