师：二十世纪是跌宕起伏的世纪，回首二十世纪的国际政治格局，我们不难发现本世纪的国际政治格局曾有三次转型，同学们知道是哪三次吗？＠评：教师设计了大角度，大跨度的问题，引导学生回顾整个叨世纪，既使学生把握宏观的“格局”问题，又可作为’‘楔子”．顺势引入本课内 Teacher: The 20th century is a century of ups and downs. Looking back at the international political structure of the 20th century, it is not difficult for us to find that there have been three transitions in the international political pattern in this century. What do the students know? @ Comment: The teacher designed a large-angle, long-span problem and guided the students to review the entire century. Even if students grasp the macro-structure problem, they can also be used as a ’wedge’.