Begg矫治器带环颊面管的长度为（）。
A.5.9mm
B.5mm
C.6.3mm
D.7.0mm
E.7.5mm
参考答案：C
No one knew ________. [ ]
A. she will come
B. if she would come
C. if she would come or not
D. whether she will come or not
检测化学物的基因突变作用选用
A．微核试验B．显性致死试验C．细菌回复突变试验D．骨髓染色体畸变试验E．姐妹染色单体交换试验
