急性上颌窦炎的症状是（）
A.头痛上午重
B.头痛下午重
C.枕部头痛重
D.持续性头痛伴面部麻木
E.无规律、无定位的头部胀痛
参考答案：B
—_______the weather like in Moscow?
—It's raining.[ ]
A. How's
B. What's
C. How does
D. What does
病原体通过哪几种方式感染？
