构造柱部位砌筑方法应砌成大马牙槎，因此通常采用“（）”法砌筑方法。
参考答案：五退五进
--When did you go to bed last night?
--I didn't go to bed _____my father got home. [ ]
A. until
B. while
C. after
缩写词i.v.的含义是
A．肌内注射
B．皮内注射
C．静脉注射
D．静脉滴注
E．口服
