(18) 属于不对称加密法。DES加密算法的密钥长度是 (19) 。
A．DES
B．IDEA
C．RC-5
D．RSA
参考答案：D
造成北美冬季灾害性天气的气流是[ ]
A、西风气流
B、极地强烈冷气流
C、墨西哥湾暖湿气流
D、台风
I don't think _____ rain this afternoon. [ ]
A. it won't
B. it's going to
C. if it's going to
D. whether it's to
