高炉料柱的透气性与焦碳的()关系极大。
参考答案:机械强度
Sally ______ dinner when I came back.[ ]
A. were having
B. was doing
C. was having
D. were doing
下列加密方式只在源、宿结点进行加密和解密的是( )。
A.端到端
B.结点到结点
C.链路加密
D.都不是