First of all, you have to stop writing code-mixing sentences. Code-mixing means you interchange the use of medium of words (henceforth Chinese and English) in sentences.
Try to write everything and listen to as much as English as possible. Don't say that you can't because it's always a matter of perseverance. You are Form 4 now and it's not too late. Honestly if you are studying in a CMI secondary school, I am not so optimistic that you will be able to get your English a hugh improvement within one-year's time.
If you are able to make friends with some English natives, that would be great, Even though they might not be able to teach you grammar, but your listening and oral skills could surely be improved.
You just have to build an total English environment for yourself.
There is also an alternative, go abroad and surround yourself with English :) I am not joking of course because this is what I have chosen. I understand normal family might not be able to affort enough to help their kids studying abroad. So what I did is to save money and go for an exchange to USA for a year. However though, you have to avoid meeting Chinese or Asian as much as possible. I went to this place where only one ABC studying in that high school. Plus, that fact that when you live with them, your English will improve in an inconceivable way! You may join the program after Form 5 as this should be the best timing :) Information for you:
http://www.afs.org.hk/hkg_ch/focus_on/high_school
Please don't mind if I write this long. Last thing, if you want to improve English just enough for your HKCEE, then you don't have to do what I mentioned above then. I was a marker for HKCEE some years ago before Syl. A and B merged, when I looked at the paper last year, I can surely tell you that it's easy!! The best way for you then is to do as much past paper as you can and learn from mistakes! They always set similar types of questions.
However though, learning English is a life-long asset! You will find yourself lost in Hong Kong and in other countries if you just focus on getting good marks in English examinations. HKCEE doesn't examine students' English level but their examination skills. Sorry to say, this is the truth.
Hope this could give you some idea~~~
2007-12-20 11:49:44 補充:
"將內容翻譯成中文" and "將你要講的英文在腦中組織成寫得出的中文, 翻譯成英文講出來" Sorry to offend, Eng. and Chi. are different! Translation is not just literal (word-for-word), but conveying the sense of the original. When you talk in Eng., you have to THINK in Eng. If you think in Chinese, it will be Chinglish!