【答案解析】One thing shocked me in the America is the culture difference between China and America.
One of my American friends, a professor in a university, has a boy at five when I was there. Such a little boy had a girlfriend at five too. The boy always invited her wherever his family went. The little boy introduced her to me when I met her the first time, "This is my girlfriend." I couldn"t help laughing. He seriously answered my laugh: "Do you think I"ll marry her? No way!"
How different the two cultures are at the point of having a girlfriend.