中 1.acceptance 2.commission 3.counter-offer 4.enquiry 5.final price 6.total price 7.unfixed price 8.firm offer 9.fixed price 10.initial price 11.irrevocable offer 12.non-firm offer 13.unit price 14.validity period 15.withdrawal of an offer 16.offeree 17.offeror 18.price adjustment clause 19.quotation 20.revocation of an offer