DL451—1991《循环式远动规约》要求远动通道的传输误码率一般不大于（）。
A.10-5
B.10-4
C.10-3
D.10-2
参考答案：A
—______ the Whites ______ to go on holiday in Hainan Island at the moment?
—Yes. [ ]
A. Do, plan
B. Are, planning
C. Will, plan
D. Is, planning
检索语言的基本成分是：________
