根尖周组织包括根尖部的（） A.牙槽骨 B.牙周膜 C.牙骨质 D.牙髓 E.龋洞

The genetic engineering, ______ progress has been very rapid recently, is perhaps the most important of all the sciences．

A．to which

B．with which

C．in which

D．for

At lunchtime, I meet my friends and we always have a great time              to each other. [ ]

A. talking

B. to talk

C. talk

D. talked

下列哪个名字不是指称徐霞客（）

A.弘祖

B.字振之

C.元亮

D.霞客

结合型文本框可以从表或 【5】 中获得所需的数据。

【17】 是数据库操作的核心。