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。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。Business letters do not have to be impersonal and formal.商业信函不一定要既没有人情味又模式化。