对于上颌后牙弓明显小于下颌后牙弓的患者，排牙方法错误的是（）

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问题单项选择题

A．首选无尖牙

B．后牙排成反

C．A区与C区互换

D．A区与D区互换

E．B区与C区互换

答案

参考答案：C

选择题

When he saw all his books _____ here and there on the floor, he knew that something terrible _____.

A．lying; must have happened

B．lie; must happen

C．lay; might have happened

D．had lain; could have happen

填空题

旋毛虫雌雄交配后（）（填卵生或胎生）幼虫，经血液、淋巴，分布到身体各处，只有在（）中才可继续发育。