成人牙周炎的早期主要症状中没有
A．牙槽骨的吸收B．牙龈炎症C．牙周袋的形成D．牙齿移位E．牙菌斑
参考答案：D
C．a1/2a-1/3=a-1/6
— What’s that terrible noise?
— The neighbors ______ for a party. They moved here a week ago.
A．prepared
B．prepare
C．will prepare
D．are preparing
