在残冠或残根上先形成金属桩核或树脂核，然后再制作全冠修复体称（）

A.嵌体

B.桩冠

C.桩核冠

D.混合全冠

E.部分冠

—I knocked into a tree when I went to the railway station for my friends.        

—I suppose you _______ too fast.        [ ]

A. drive                                

B. are driving        

C. drove                              

D. were driving