下列哪种技术不是实现防火墙的主流技术（）
A.包过滤技术
B.应用级网关技术
C.代理服务器技术
D.NAT技术
参考答案：D
暑温的治则是（）。
A.清泄暑热
B.清暑益气和中
C.清暑益气生津
D.清暑凉营养阴
E.滋养肺胃之阴
I can’t remember how many years ago _____ a fight broke out between the husband and the wife.
A．it was when
B．was it that
C．it was that
D．was it when
