以下不是智齿冠周炎常见原因的是()。
A.牙齿阻生
B.牙龈盲袋形成
C.机械压力
D.牙髓炎
E.细菌侵入
参考答案:D
光缆接续的内容应包括:()。
As we know, blood types A and B cannot receive AB, but AB may receive A or B. Type O can give to any other group; hence it is often called the() donor.
A.general
B.popular
C.universal
D.common