上颌平面导板能改正（）
A.后牙反
B.前牙反
C.压低下前牙
D.导下颌向前
E.改正前牙开
参考答案：C
世界上跨经度最广的大洲是[ ]
A．北冰洋
B．南极洲
C．欧洲
D．南美洲
Don't forget to put the book back on the shelf, _______? [ ]
A. do you
B. don't you
C. will you
D. won't you
