X线片上可以无明显骨质破坏表现的是
A．急性根尖炎
B．根尖囊肿
C．慢性根尖脓肿
D．根尖肉芽肿
E．慢性根尖脓肿急性发作
参考答案：A
— Wasn't it Dr Wang who spoke to you just now?
— ____.
A．I didn't know he was
B．Yes， it was
C．No， he wasn't
D．Yes， he did
事件顺序记录站间分辨率应小于（）。
A.1Oms
B.20ms
C.30ms
D.40ms
