Hi, Eskaslike
Thanks again for the feedback. What do you mean by sounding natural? Do you mean that my speech flows well? I'd like to know what else I can do to get closer to native.
Yes, I definitely mean your speech flows well. "Sounding natural", means that you sound more like a native English speaker. :up:
1) In my experience, the way to improve anything you are trying to learn is, to concentrate more upon the things you either can't do, or don't do well, and less on the things you already know, or can do well. (i.e. In this instance, practise letters, words, or phrases which you find, or know that Chinese learners find, difficult).
This can also apply to the reading, writing, or speaking English. If you have more difficulty speaking it, than reading or writing, then focus more on that aspect.
The greatest improvement can only, and therefore will always, come from practising what you find the hardest.
2) When we learned English
as children, we used to learn the difficult sounds in words, or combinations of words, by using "tounge twisters". These are a type of word game, usually played by children but, whatever your age, they will help your speed, fluency, and intelligibility, as they get you to focus on making the right sounds quickly.
Practicising them a lot, although sounding silly at the time, will help you to sound much more natural when speaking later.
The one I always remember is:
"Betty Botter bought a bit of butter, but she said, "This butter's bitter, if I put this bitter bit of butter in my batter, it will make my batter bitter!". First language English speakers find this difficult to say quickly, which is why it is good for learners to use.
Similarly; "How much wood would a wood-chopper chop, if a wood-chopper could chop wood" This is the BrE variation.
You will frequently see the AmE variation as,
"How much wood would a woodchuck chuck if a woodchuck could chuck wood". The reason why it isn't generally used in BrE is because British people wouldn't really understand what a "woodchuck" is.
In BrE a "wood-chopper" is an informal, or colloquial way of saying "lumber jack". The reason it is used is to make the speaker have to vary they way they say the different "o" sounds found in the sentence.
The BrE version may not work in AmE, possibly because they may just think more that a "wood-chopper" is an axe, and so for them it possibly doesn't work. They will understand what a "woodchuck" is, which is why they use it in their version.
Remember these are fun, and may deliberately contain bits of poor grammar, or funny words in order to make them so. They are good for practicising sounds quickly and properly, and as a bit of learning fun.
3) What type of variation of English do you need, or want, to learn? If you want to speak, or mainly deal with Americans, then focus more on their ways. If you want to learn to become more like an Australian, then use theirs. The same is true if you wish to use British English. Overall, the variations are not that great, because we all understand each other, for the vast majority of the time! But try to learn from all first language English speakers, because it will help you understand why different words and phrases are used by different people from around the world. But as I have said, focus on the variation of English which you need, or wish, to use.
This web page is good because it contains a simple story called "Arthur the Rat" which contains all the sounds found in the English language.
http://ask.metafilter.com/25526/Sentences-containing-every-English-phoneme. I note that, further down the same page, someone has pasted a link to "Please Call Stella", so you may have already found "Arthur the Rat".
However, I think this is useful because it gives you the text, and also the link to these audio files read by first language users from all the English speaking areas in the world.
http://alt-usage-english.org/audio_archive.shtml#Arthur (For me, the MP3 files work). So, you can chose the story in the regional variation of the language on which you wish to focus.
When speaking this story, note where you stumble or have difficulty with the words, especially if the difficulty persists after quite a few readings. These are the words or sounds to focus on, in order to improve.
4) Connected to 3) above: Find, if you can, on the internet, television or film, an English speaker that you like, and who you know speaks very well in the English regional variation you are trying to emulate. They may not be infallible, but generally aim to mimic them as closely as you can. After all, this is what all children do in any language, by trying to copy their parent's speech. That is why, with practise, they end up as natural sounding speakers.
5) Try, always, to know and maintain a distinction between formal and informal English and when to use them. This is true when writing, or speaking. It will reap rewards. Firstly focus on the formal, or at least semi-formal version. This is because it will help you gain an understanding of usage.
I think that is quite a lot to think about, but hopefully, some of it will be useful to you. 
