在人体内，神经冲动的传导不可能由

阅读下面短文，按照句子结构的语法性和上下文连贯的要求，在空格处填入一个适当的词，或填入括号中所给单词的正确形式（每空不多于3个单词）。

    We are living in a time when the world is becoming a “village”. People travel around the world ____ sightseeing, studying, working or volunteering. Perhaps in the near future, you will also become one of those people.

    Spending time in a foreign country is an____ (excite) and life-changing experience. You see different sceneries, taste nice food and meet people with all kinds of backgrounds. And ____ (important) thing of all, you explore and even become a part of the local culture.

    Your stereotypes(成见) are broken down. You may find French people are not always “romantic”. ____ (America) don't eat McDonald's all the time. And you won't get malaria(疟疾) from a mosquito bite(蚊子叮咬) in Africa.

    ____, culture shock may hit you. Things you take for granted(认为理所当然) at home may no longer be that way in a foreign country. Not everyone thinks like you or does things the way you've always____ (do). Their tea tastes different. They don't talk____ (loud) in restaurants. Some might not care much about your life, ____ you may even feel they are a bit cold. It is not better or worse. It is just different. ____ you can do is to take in the differences, while trying to be respectful and humble(谦虚的). Each time you open up____ (you) mind a little more, you become a better person.