How do you know that your English is terrible and is not improving? If you are studying I believe that all the time you re improving. At least I think this way. I'm sure that today I am better than yesterday. Don't forget that even native English speakers have problems with grammar. So, let go ahead. Good lucky!

English is not hard language, but it's upto you, when you think something is difficult, that really becomes difficult for you. so, make up your mind and motivate yourself. I 'm sure that you can do it. good luck

I think more difficult is on lexicle, as part of Grammar

It depends on your motivation.

Actually learning another language is interesting.

It's hard because English is very different from Chinese. Chinese is also hard for English speakers.

Make sure you have good study habits and keep trying!