（）是决定传播性质和传播媒介性质的关键性因素。
A．社会制度
B．大众传播制度
C．文化制度
D．经济制度
参考答案：B
I'm sorry. I _____________ you__________ to me.
A．don't know; are speaking
B．don't know ;were speaking
C．didn't know; were speaking
D．didn't know; are speaking
传染性非典型肺炎的人间传播途径不包括（）
A.近距离飞沫传播
B.接触传播
C.气溶胶传播
D.虫媒传播
E.血液传播
