通信信道的类型有两类:广播通信信道和( )。
A.系统信道
B.交互信道
C.点一点通信信道
D.本地系统
参考答案:C
解析: 通信信道的类型有两类:广播通信信道和点-点通信信道。
妊娠5个月以上的妇女引起肾盂肾炎最常见的原因是
A.上呼吸道感染B.膀胱炎C.血行感染D.妊娠子宫压迫输尿管E.淋巴道感染
Our school forbids_____ ,that is to say, we are not allowed ____ at school.
A.to smoke, to smoke
B.students’ smoking, smoking
C.students’ to smoke, smoking
D.students’ smoking, to smoke