1)在开头出现;
2)在结尾出现;
3)在开头和结尾同时出现，首尾呼应;
4)有些文章的中心思想贯穿全文，并没有用一句话明确表达出来，这就要求学生学会归纳概括。
(三)实战演练
2 Decision thinking is not unlike poker—— it often matters not only what you think, but also what others think you think and what you think they think you think. The mental process is similar. Naturally, this card game has often been of considerable interest to people who are, by any standards, good thinkers.
The great mathematician John von Neumann was one of the founders of game theory. In particular, he showed that all games of “perfect information”, games like chess where the players can't hide anything or play tricks; they don't win by chance, but by means of logic and skills. Then there are games of “imperfect information”, like poker, in which it is impossible to know in advance that one course of action is better than another.
One mistaken idea about business is that it can be treated as a game of perfect information. Quit the reverse. Business, politics, life itself are games which we must normally play with very imperfect information. Business decisions are often made with many unknown and unknowable factors which would even puzzle best poker players. But few business people find it comfortable to admit that they are taking a chance, and many still prefer to believe that they are playing chess, not poker.
The subject discussed in this text is _____
a. the process of reaching decision
b. the difference between poker and chess
c. the secret of making good business plans
d. the value of information in winning games