白化病是由隐性致病基因控制的一种遗传病。一对正常的夫妇生下一个白化病的儿子,这对夫妇的基因组成是 [ ]
A.AA和Aa
B.Aa和AA
C.Aa和Aa
D.aa和aa
答案:C
患者女,15岁,口唇闭时呈现口腔周围肌肉的高度紧张感,下颌颏部更为明显。上下颌牙列拥挤明显,牙弓狭窄,覆6mm,覆盖6ram,磨牙呈Ⅰ类咬关系。ANB5.5°,FMA35°,UI~SN110°,IMPA85.5°。
在远中移动尖牙时,最好使用()
A.开大螺旋簧
B.Ⅱ类牵引
C.尖牙向后结扎
D.弹力橡皮圈
E.链状橡皮圈
______ today, he would get there by Friday.
A.Were he to leave
B.If he had left
C.Did he to leave
D.Had he left