境内商户开通（）以后，签购单上有人民币交易金额和和外币交易金额可供持卡人选择。
参考答案：DCC
转K5、转K6型转向架卡入式滑槽磨耗板磨耗大于（）时须更换。
Come as early as possible ;________,the better.
A． early
B． the earliest
C．earlier
D．the earlier
