牙周病患者在使用牙线前应首先进行()
A.刷牙
B.漱口
C.牙签去除菌斑
D.龈上洁治和根面平整
E.牙龈按摩
参考答案:D
Changes may be requested by any stakeholder involved with the project, but changes can be authorized only by()
A.executive IT manager
B.projectmanger
C.change control board
D.projectsponsor
座舱高度达到多少时,座舱高度警告喇叭会响:().
A、8000FT
B、10000FT
C、14000FT
D、17000FT