()防火墙是基于应用层的防火墙
A.安全服务型
B.层过滤型
C.包过滤型
D.代理服务型
参考答案:D
One minute she burst into _______, and the next she burst out ______.We just couldn’t catch her mood at any moment.
A.crying, laughter
B.tears, laughing
C.tears, laughter
D.crying, laughing
下列试验中,所选装置不合理的是
① ② ③ ④ ⑤
A.分离Na2CO3溶液和CH3COOC2H5,选④
B.用CC14提取碘水中的碘,选③
C.用溴水除去甲烷中混有的乙烯,选⑤
D.粗盐提纯,选①和②