玻璃离子粘固粉
A.固化时收缩,对牙髓有刺激性B.固化期15分钟C.无粘接性,需制备良好的固位形D.与牙有化学粘结E.固化时体积无变化
参考答案:D
Everyone ______________ to their teacher in the classroom. [ ]
A. are listening
B. is listening
C. listened
D. listen
操作由二人实施,每项遥控操作时必须有指定的操作人并填写在执行操作票中。