在（）传输中，比特一次一个地通过一个线路传输。
A.异步串行
B.同步串行
C.并行
D.A和B
参考答案：D
You'd better _____ upstairs and tell the children _____ make so much noise. [ ]
A. go, not to
B. go, don't
C. to go, not to
D. to go, don't
我国面积最小的省级行政区是[ ]
A．澳门
B．香港
C．北京
D．海南
