以下四类传播活动中最有效的是（）.
A.内向传播
B.人际传播
C.组织传播
D.大众传播
参考答案：B
全口义齿上颌基托纵折的原因，除外下列哪项（）。
A.腭侧基托太薄
B.硬区未缓冲
C.上后牙排在了牙槽嵴顶的颊侧
D.牙槽嵴吸收不均匀
E.唇系带处磨除过多
I am going to Qingdao and stay there for a week. _____ you are there, would you please
buy some books for me? [ ]
A. If
B. While
C. Since
D. As soon as
