--What are you going to do this weekend？

--I will go to visit my grandparents _____ I have time.

A. as far as     B. as much as      C. as long as     D as many as

患者，男，21岁。左上中切牙外伤3年逐渐松动。检查左上中切牙变色，Ⅲ°松动，根吸收1/2。此牙缺失后，目前最佳的修复方法是（）

A.即刻牙再植术

B.延期牙再植

C.牙种植

D.异体牙移植

E.烤瓷桥修复