理想的下颌前牙冠桩直径为根管径的（）
A．2/3
B．1/5
C．1/4
D．1/3
E．1/2
参考答案：D
Mr Wang’s lessons are _____, so his students like him very much. [ ]
A. alive
B. live
C. living
D. lively
小肠能够吸收食物中的胆固醇的
A．20％B．25％C．30％D．35％E．40％
