请将下面5个词按正确的形式填入空格（fulfill，instructions，accompanied，required，authority）。Dear Sirs,The （1） from Browning & Sons, received through our Hong Kong office, we have opened an irrevocable letter of credit for $55,500 in your favor, valid until 30 November next. You have （2） to draw on us at 60 days against this credit for the amount of your invoice upon shipment of 2000 tons of Steels to Browning & Sons.Your drafts must be （3） by the following documents, which are to be delivered to us against our acceptance of the draft, Bill of Lading in triplicate, Commercial Invoice, Insurance Certificate and Certificate of Origin. Provided you （4） the terms of the credit we will accept and pay on maturity the draft presented to us under this credit and if （5） , provide discounting facilities at current rates."请作答。