1. Intention angle: The articles in the textbook are all model essays with both literary quality and beauty. Some of them belong to the same topic, but their intentions are different.

2. Angle of material selection: Everyone's life experience, temperament, education and fate determine their different material selection, so when writing, there will be different angles of material selection.

3. Stylistic perspective: In order to express feelings and thoughts, it is sometimes necessary to choose different styles according to different situations.