粘膜下脓肿首选应急处理为（）
A.局部封闭
B.切开引流
C.服用消炎、止痛药
D.开髓或扩大穿髓点
E.去除病髓后根管引流
参考答案：B
Nearby _____ in which they had spent their summer vacation. [ ]
A. was two houses
B. two houses were
C. were two houses
D. are two houses
投资项目施工阶段的基本特征是( )。
A．智力化B．智力和技术的双重性C．劳动性D．资金和劳动的双重性
