单项选择题 When should the buyers open a letter of credit in a transaction？（）

单项选择题 A gentleman must help a lady whom has escorted to the table，to all she wishes；but it is improper for him to offer to help other ladies who have escorted.The word "escort"means ？（）

单项选择题 What is the "continental"style of dinning？（）

单项选择题 For American Table Manners ，if your soup is too hot to eat.What should you do？（）

单项选择题 In Basic American Table manners，（）on the table are acceptable only between course，not while you are eating.