【简答题】Our quotation ______ 30,000 tons of corn is valid for 10 days.
【简答题】用于核磁共振研究的核的自旋量子数必须 ____________ 。
【单选题】______, we are airmailing you our latest quotation-sheet.
【简答题】We very much regret that we are unable to satisfy your special requirements for the item of packing in our quotation sheet dated 30 th .