串级密封日常维护除了清洁卫生以外主要是()。
A、缓冲罐加油
B、冷却水畅通确认
C、更换压力表
D、缓冲罐顶放空阀门是否关闭确认
参考答案:A, B
When a discussion is under way, everyone is welcome to have the_________ in class.
A floor B time C chance D right
重度慢性牙周炎的确诊指标有()
A.牙周袋深度>6mm
B.附着丧失≥3mm
C.牙槽骨吸收超过根长1/2
D.多根牙有根分叉病变
E.牙齿松动