鼻窦黏膜囊肿最常见于（）。
A.上颌窦
B.额窦
C.筛窦
D.蝶窦
E.无差别
参考答案：A
A．( Working is more important than having a holiday
B．( A driver should be more careful than a pedestrian
C．( In driving, it is always safety that comes first
D．( It is dangerous to drive fast in crowded areas
2007年11月8日，太阳直射在（）
A．赤道
B．回归线上
C．赤道和北回归线之间
D．赤道和南回归线之间
