What role does it play in the text and how is it judged? For example, there are: leading out the following, leading out the center, naming the center, connecting the preceding with the following, etc. How should I use it? Use of sentences and words:

1. This sentence is called a turning sentence. For example, in Tolstoy's The Poor, Sang Na saw the lighthouse and thought of his neighbor Simon.

2. introduction This can also be called paving the way for the full text. For example, the first sentence in Tolstoy's Anna karenin: "All happy families are similar, and each unhappy family is unhappy in its own way."

3. Emphasize the theme. Generally, this kind of sentence will appear at the beginning and end of the article to emphasize the theme and central idea of the article.

4. Contrast. Many books describing the poor will use a description of the things around them, comparing the simple facilities with the magnificent palaces of the rich, and comparing the nobility of the poor with the meanness of the rich. This will cause the reader's * * *

I think there must be many more. But after all, I am a primary school student with limited experience, so the usefulness of summing it up is limited. Please forgive me!