8-year-old children learn the Oxford tree well 1-2. As a graded reading material, Oxford Tree is really good for children's English enlightenment. 4-6-year-old children correspond to the stage of 1-3, which is suitable for children with a certain English foundation and not suitable for children who have just begun to enlighten (except parents who are proficient in English). The content of Oxford Tree 1-2 is a little difficult for children who are just beginning to be enlightened. 8-year-old children's knowledge of English will not be too blank, and it is appropriate whether they have studied English systematically or not.