The knowledge point to be investigated in analyzing this problem is futures trading in international trade. Item A: The commodities traded in the futures exchange are only traded according to the prescribed grades and samples, and most of the commodities handled are single primary products. Therefore, item A is correct. Item B: Futures trading generally does not involve the transfer of physical ownership of goods, but only the transfer of ownership of futures contracts. After the transaction, the buyer and the seller did not really realize the transfer of the goods, but agreed to handle the delivery within a certain period of time, and completed the contractual obligations by buying before selling or selling before buying. Therefore, item B is correct. Item C and D: In futures trading, buyers and sellers are mainly completed through hedging transactions. Therefore, item C is correct and item D is wrong. To sum up, the correct answer to this question is ABC.