采用托收结算方式的买卖合同项下,出口商制单的首要依据是( )。
A.买卖合同
B.信用证
C.《URC522》
D.《UCP600》
参考答案:A
.No one knows exactly when our ancestors started talking,but new evidence suggests _______might have happened a long time ago.
A.which
B.what
C.it
D.they
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