计算机网络按照通信距离或覆盖范围可以分为（）。
A.局域网
B.广域网
C.城域网
D.光纤网
参考答案：A, B, C
During the examination we are required to stay in our seats, keep our eyes on our work, ____ to anyone.
A．instead of speaking
B．rather than speak
C．and not to speak
D．but would not speak
下列各种瓣膜病，可闻及心尖部舒张中晚期隆隆样杂音的是（）
A.二尖瓣关闭不全
B.二尖瓣狭窄
C.主动脉瓣狭窄
D.主动脉瓣关闭不全
E.三尖瓣狭窄
