客户签约使用交行电子商业汇票系统必须开通（）业务。
A.交行电子对账
B.交行企业网上银行
C.单位结算卡
D.对公银信通
参考答案：B
There is a man at the reception desk who seems very angry and I think he means（）trouble.
A. making
B. to make
C. to have made
D. having made
关税具有( )、( )、( )等特点，具有( )、( )、( )等作用。
