I know it isn’t easy to learn English well,but I have some ideas that may help.You said you couldn’t understand people who talked fast.Well,you can try to listen for the most important words,not every word.You can also do lots of listening practice.I think it’s one of the secrets of becoming a good language learner.Another thing that I think important is English grammar.
In order to learn it well,you have to take a lot of grammar notes in every class.You can write English sentences using the grammar you are learning.You can also read more English books.Reading is as important as listening for us to learn English well.If you do so,I believe that you can learn English very well later on.不知道是不是这个啊,我们写的时候就是这篇