21. In a/an _____ transaction, the sight draft is presented to the importer with the shipping documents, and the importer pays immediately. (A)O/P (B)O/C (C)D/P (D)D/A 。

6. Much as we would like to do business with you, _____. (A)we are unable to accept your order at the price you requested (B)we will be pleased to fulfill your order No. A116 (C)we are prepared to give a further reduction of 5% i n our quoted price (D)we expect to receive a new supply shortly 。