That's right. The concrete unity of objectivity and subjectivity is that in space, we should have an overall understanding of the object of knowledge. For example, in the story of the blind touching the elephant, every blind person has a correct understanding of each part of the elephant, but they have a wrong understanding of the whole part. For example, if an elephant's tail is like a snake, it is said that an elephant is like a snake, and the part is regarded as a whole, which violates the concrete unity of subjectivity and objectivity. The unity of subjective and objective history is that in time, our thoughts should keep up with the changing reality. For example, when the sword fell into the water, the mark he drew on the ship's side was correct, but when the ship docked, it was wrong for him to fish for the sword at the original mark, because the objective reality had changed. The so-called unity of subject and object is the unity under specific time and space conditions. Our understanding should conform to the reality of specific changes. I am a high school political teacher, and I use the above examples to help students understand this abstract principle in class.