[C]various virtues manifest themselves exclusively among friends

　　[D]social interrelationships equal the complex set of cultural conventions

　　7. Families in frontier settlements used to entertain strangers _____.

　　[A]to improve their hard life

　　[B]in view of their long distance travel

　　[C]to add some flavor to their own daily life

　　[D]out of a charitable impulse

　　8. The tradition of hospitality to strangers _____.

　　[A]tends to be superficial and artificial

　　[B]is generally well kept up in the United States

　　[C]is always understood properly

　　[D]was something to do with the busy tourist trails

　　[第5题答案及题解页数] D 第页

　　[第6题答案及题解页数] A 第页

　　[第7题答案及题解页数] C 第页

　　[第8题答案及题解页数] B 第页

　　[长难句突破]

　　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.

　　主体句式：The casual friendliness of many Americans should be interpreted…

　　结构分析：这个句子的复杂成分在于be interpreted后面的内容，这个部分由三个并列结构构成，分别为“neither as superficial”、“nor as artificial”和“but as the result of a historically developed cultural tradition”。这种并列结构对应于汉语里面的“不是……也不是……而是……”。