中央性颌骨骨髓炎急性期的X线特点是
A．骨质无明显变化
B．斑点状破坏
C．皮质外新骨质增生
D．死骨形成
E．骨膜反应
参考答案：A
---It’s a long time _____ I saw you last.
---Yes, and what a pity it is now that it will be a long time _______ we see each other again.
A．before; since
B．since; when
C．since; before
D．when; before
有限应变
