如果根尖肉芽肿在拔除牙齿后仍残留在颌骨内可形成
A．始基囊肿
B．残余囊肿
C．含牙囊肿
D．角化囊肿
E．根尖周囊肿
参考答案：B
— How does your sister go to work in the morning?
— _____. Because the office is near our home. [ ]
A. By bus
B. By car
C. On foot
D. It's OK
死亡3人以上、9人以下，重伤20人以上，直接经济损失30万元以上，不满100万元的，属于( )。
A．一级重大事故
B．二级重大事故
C．三级重大事故
D．四级重大事故
