(阅读理解)In a business talk between a Chinese exporter and a HK buyer in a trade fair about the export of sneakers, the HK buyer claimed that the import quota is needed as the final destination of goods is USA, while the expiry time of the quota owned by the buyer is at the end of June, so the shipment must be made by the end of June otherwise the HK buyer has to take responsibility of contract breach. As the term of the contract, the exporter was required to pay USD300,000 as a guaranty deposit, and the client promised to issue an irrevocable L/C from a well-known HK bank. The exporter overlooked the clause saying“one shipment approval certificate signed by the L/C applicant must be presented with shipment documents” in the credit when it received the L/
C: When the exporter made presentation of shipment documents to the bank, the exporter was aware of the term and required the HK buyer to cancel the clause or issue the concerning certificate, but the HK buyer always put it off. At last, the exporter couldn't make presentation and lost the deposit. Please make an explanation of what we can learn from the case.(1) (多选题) Which of the following judgments is reasonable on the case?
选项：

A: It is a case about the cheat of the exporter's deposit.
B: On receipt of an L/C, the exporter must examine the credit carefully to avoid the soft clause and refuse to pay the deposit.
C: The shipment of exporter is an obligation stipulated in the sales contract, which doesn't need the approval of the buyer.
D: The requirement for the exporter to make shipment on receipt of the approval of the buyer is a soft clause of the L/
C: