直视钳穿法中，寻找输精管并固定之方法是下列哪一种（）
A.注射针头固定法
B.穿针引线法
C.针挑法
D.钳穿法
E.以上都不是
参考答案：E
幼儿不良习惯造成错时，应在几岁以后采用矫治器治疗（）
A.2岁
B.4岁
C.6岁
D.8岁
E.12岁
The biggest whale is _______ blue whale, which grows to be about 29 meters long-theheight of
_______ 9-story building. [ ]
A. the; the
B. a; a
C. the; a
D. a; the
时，应在几岁以后采用矫治器治疗（）
biggest whale is _______ blue whale, which grows to be about 29 meters long-theheight of 