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
1. The easy way out isn't always easiest. I learned that lesson when I decided to treat Doug, my husband of one month, to a special meal. I glanced through my cookbook and chose a menu which included homemade bread. Knowing the bread would take tine, I started on it as soon as Doug left for work. As I was not experienced in cooking, I thought if a dozen was good, two dozen would be better, so I doubled everything. As Doug loved oranges, I also opened a can of orange and poured it all into the bowl. Soon there was a sticky dough (面团) covered with ugly yellowish marks. Realizing I had been defeated, I put the dough in the rubbish bin outside so I wouldn't have to face Doug laughing at my work. I went on preparing the rest if the meal, and, when Doug got home, we sat down to Cornish chicken with rice. He tried to enjoy the meal but seemed disturbed. Twice he got up and went out side, saying he thought he heard a noise. The third time he left, I went to the window to see what he was doing. Looking out, I saw Doug standing about three feet from the rubbish bin, holding the lid up with a stick and looking into the container. When I came out of the house, he dropped the stick and explained that there was something alive in our rubbish bin . Picking up the stick again, he held the lid up enough for me to see. I felt cold. But I stepped close and looked harder. Without doubt it was my work. The hot sun had caused the sough to dough to double in size and the fermenting yeast (酵母) made the surface shake and sigh as thought it were breathing . It looked like some unknown being from outer space. I could see why Doug was shaken. I had to admit what the “living thing” was and why it was there. I don't know who was more embarrassed (尴尬) by the whole thing –Doug or me.
The writer's purpose in writing this story is ___________
a. to tell an interesting experience.
b. To show the easiest way out of a difficulty.
c. To describe the trouble facing a newly married woman
d. To explain the difficulty of learning to cook from books