I record my business letters, and my secretary transcribes them.我将商业信函口述录音，由秘书转成文字。During the first week of the secretarial course we learned how to write business letters.上秘书课的第一周，我们学会了如何写商业信函。It's always a good idea to save business letters, bills, and receipts.把商业信件、账单和收据保存起来不失为好主意。