下列哪项非大头瘟的诊断要点（）
A.多发于冬、春季节
B.起病较急
C.头面红肿
D.肌肤发斑
E.咽喉肿痛
参考答案：D
根据句意提示补全单词。
1. Bill Gates ___________ his interest in software when he was only 13.
2. Bill Gates and his friends often ___________ fortune magazine for fun.
3. Bill Gates ___________ Harvard University that many people dream of.
4. Bill Gates is a friendly, funny and ___________ person.
5. Everyone agrees that he is hardworking, ___________ and confident.
下列哪项引起回声增强（）。
A.强反射结构
B.传播速度误差
C.Snell定律
D.弱衰减结构
