1．The casual friendliness of many Americans should be interpreted neither as superficial nor as artificial, but as the result of a historically developed cultural tradition.
　　【译文】许多美国人随意表现出的友善不应该被看作是表面或虚假的应酬，而应看作是一种文化传统历史发展的结果。

　　【析句】句子的主干结构是The casual friendliness should be interpreted。注意neither… nor… but结构的使用，这种结构表示“既不是……也不是……而是……”，重点在but之后。

　　【讲词】casual意为“轻松的，随意的”。I only have a casual acquaintance with avant-garde music.（我对先锋派音乐略知一二。）He made a casual remark at the reception.（他在招待会上作了即席发言。）superficial意为“肤浅的”。Only the most superficial mind would assert nowadays that man is a reasonable creature.（如今只有最简单的头脑才会断言人是有理智的动物。）The manager made only a few superficial changes in the feasibility plan.（经理只在可行性报告中做几处无关紧要的小改动。） artificial意为“人工的；造作的；虚假的”。The policy no doubt set up artificial barriers against women and minorities.（这一政策无疑设置了歧视妇女和少数民族的人为障碍。）This brand of tinned beans contains no artificial colouring.（这种品牌的罐装青豆不含人造色素。）

　　2．As is true of any developed society, in America a complex set of cultural signals, assumptions, and conventions underlies all social interrelationships.
　　【译文】像其他发达国家一样，在美国，人际关系的背后是一系列复杂的文化符号、信念和习俗。

　　【析句】句子的主干结构是a complex set of cultural signals, assumptions, and conventions underlies all social interrelationships。as在句中是代词，表示“这一情况，这一事实”。

　　【讲词】as is是一个常见的表达方式。The night had turned cold, as is usual around here.（夜晚变得很冷，在这一带经常如此。）As is described in the picture, "love is a lamp which is brighter in darker places."（如同画中所描绘的那样，“爱是一盏灯，在暗处更显明亮。”）assumption意为“承担，担当；假定；设想”。His assumption of power was welcomed by everyone.（他掌权为大家所欢迎。）The hostess bustled about with an assumption of authority.（女主人摆出一副权威的样子忙来忙去。）