There are many stereotypes about the character of people in vari

There are many stereotypes about the character of people in various parts of the United States．In the Northeast and Midwest,people are said to be closed and private．In the South and West,however,they are often thought of as being more open and hospitable．Ask someone from St．Louis where the nearest sandwich shop is,and he or she will politely give you directions．A New Yorker might eye you at first and after deciding it is safe to talk to you,might give you a rather unexpected explanation．A person from Georgia might be very kind about directing you and even suggest some different places to eat．A Texan just might take you to the place and treat you to lunch. American stereotypes are abundant．New Englanders are often thought of as being friendly and helpful．Southerners are known for their hospitality and warmth．People from the western part of the United States are often considered very outgoing．These differences in character can be traced to different factors such as climate,living conditions,and historical development. When travelling from place to place,Americans themselves are often surprised at the differing degrees of friendliness in the United States. The main idea of the passage is__.
A、even Americans are surprised at the big differences among themselves
B、there are many differences in character in different parts of the USA
C、there are many reason for the differences
D、stereotypes about people are not necessarily true
【正确答案】：B
【题目解析】：文章首先描述了美国不同地区人们的性格特征的一些刻板印象，例如东北和中西部的人被认为是封闭和内向的，而南部和西部的人则被认为是开放和好客的。接着，通过描述来自不同州的人如何对询问三明治店位置的人的反应，进一步展示了这种性格差异。然后，文章指出这些性格差异可以追溯到气候、生活条件和历史发展等因素。最后，文章提到即使是美国人在旅行时也会对自己国家内不同地区的友好程度感到惊讶。 然而，文章的核心内容是关于美国不同地区人们性格的差异，并通过具体例子和可能的原因来支持这一点。选项A虽然提到了美国人对自己之间差异的惊讶，但这只是文章的一个辅助观点，不是主题。选项C虽然提到了差异的原因，但这也是支持主题的一个方面，不是主题本身。选项D讨论了对人的刻板印象可能不准确，这在文章中没有直接提及。 因此，最符合文章主题的是选项B，即“美国不同地区人们的性格有很多差异”。