To be honest, I don't know but it seems like an enormous waste of your time to learn English this way, especially as your English is already very good. Having been a secondary school teacher and having wept copious tears over the appalling standard of many native English-speaking students' language, I can't say I recommend the way they learn it! The best way to improve your English is to get a good English grammar textbook with exercises and post here for any corrections you need. After that you should read as many English books as you can. Choose books you would read in your own language as otherwise you are going to get very bored and demotivated very quickly and give up. I love murder mystery and thrillers myself so I read those as I am motivated to find out what happens. I can recommend buying a portable DVD player and getting DVDs in English with English subtitles (preferably with the option of Chinese as well). That way you can stop and start it to look up a word, or rewind and listen again. The subtitles are unlikely to be exactly the same as the speech but you will get a sense of achievement when you start to be able to recognise the difference. The reason I like this method is that you can whip the machine out when you are out and about somewhere and would otherwise not be learning anything. Waiting for the dentist, the bus, the train, etc. become far more enjoyable and you are learning something at the same time. I also recommend audio books which you should be able to download from audible.com or amazon and listen to them when you are travelling or doing chores round the house i.e. whenever you can't watch your DVD because you need to do something. There are software programs that will trick your computer into thinking that you are in England. If you can get your hands on one of these, you can watch programs on BBC iplayer which generally have subtitles as well.