Background I feel that there are still many deficiencies in my English, so I studied some English grammar a while ago. In fact, many of them are things that need to be learned in junior high school, but I didn’t take it seriously at that time, and I didn’t learn anything from the teacher. I can’t say that I gave everything back to the teacher, because the scenarios where English is needed in work are increasing, so I still followed Youtube and learned a lot, so I wrote this summary article.