— Who should be responsible for the accident? 

— The boss, not the workers. They just carry out the order _____. [ ]

A. as told

B. as are told

C. as telling

D. as they told

下列何者不是固定矫治器的优点（）.

A.固位良好，支抗充足

B.能使多数牙移动；整体移动、转矩和扭转等移动容易

C.能控制矫治牙的移动方向

D.施力过大疼痛时，患者可自行卸下，避免损伤牙体牙周组织

E.体积小，较舒适