砌碹支护立碹胎时一定要和巷道（）对准，保证碹体中心与巷道中心一致。
A.中线
B.腰线
C.中心和腰线
D.水平方向
参考答案：C
______ a little more time to think, he might have acted more sensibly.
A．If he took
B．If he has taken
C．had he taken
D．Should he take
Access中，______字段类型的长度由系统决定。
A．是/否
B．文本
C．货币
D．备注
