龋只累及釉质或牙骨质（）
A.浅龋
B.中龋
C.深龋
D.邻面龋
参考答案：A
肠道手术后导致感染的常见厌氧菌是
A．大肠杆菌B．类杆菌C．粪球菌D．沙雷菌E．克雷白杆菌
________ he was very ill, he still went on working..
A．Because
B．For
C．Though
D．/
