各国的文化和历史常识内容范围比较广,我举几个例子,比如：《老人与海》的作者?美国的那些著名建筑或者联合国的名称.世界最老

there have thirteen cross lines and fifty stars constitutes the american flag,and the thirteen cross lines represents early independent states and fifty stars represents the whole states.
the author of the book is Ernest Miller Hemingway.
the famous building in america i think is the Empire building ,world trade and business center,and the white house.