This memorial was built _______ those heroes who laid down their lives for the liberation of the

poor people.[ ]

A. in memory of          

B. to remember                            

C. for the memory of      

D. to the memory of  

患者女，28岁，全口重度四环素牙，要求上下前牙烤瓷冠修复。X线片显示上下前牙牙周均元明显异常

根据保护牙体牙髓组织健康的原则，牙体预备后应该（）.

A.硅橡胶取模

B.口服消炎药

C.戴暂时冠

D.收缩牙龈

E.牙周上药