填入合适的介词 Dear Sirs, We confirm having received your inquiry of August 20 (1)____ our gold pens CIF London. Complying (2) ____ your request, we are making you a firm offer as follows: Commodity: Seagull Brand Gold Pens Specification: As per attached list Quantity: 1,000 dozen Packing: In cartons of 100 dozen each Price: (3) ____ £ 24 per dozen CIFC 5% London Shipment: During October/ November, 2014. Payment: (4) ____ confirmed, irrevocable L/C. This offer is firm, subject (5) ____ your reply reaching us before September 1. Please note that we have offered you our most favorable price and thus we are unable to entertain any counteroffer. We are hoping that you will accept our offer as soon as possible. Yours faithfully,