______可用来解决内联网和外联网的安全问题。
参考答案：防火墙
-Who helped Betty tidy up the bedroom just now?
-_________. She cleaned it all by herself.[ ]
A. Somebody
B. Nobody
C. Everybody
D. Anybody
下列哪一项不属于小青龙汤证的主症（）
A.烦躁
B.发热
C.干呕
D.咳
E.微喘
