上颌窦穿刺多在下鼻道、距下甲前端1．5cm的下甲根部是因为：（）
A.骨壁较薄
B.离上颌窦较近
C.血管较少
D.痛苦小
E.以上都不是
参考答案：A
It's the first overseas trip that President Hu Jingtao has made this year,_______?[ ]
A. is it
B. isn't it
C. has he
D. hasn't he
丧葬用品批发服务
