The sentence is long and confusing. It will be a much clearer communication if you eliminate the commas, and write 4 separate sentences, like this. Also, it is an error to write that Australia "locates"; because actually, Australia does not do that. No Country "locates" itself. This is how you would write to communicate these ideas. #1 Australia is located in the south of the world just opposite China. #2 There are so many differences between the two countries. #3 I want to go to Australia to see a very different world. #4 I think it will be very exciting. Do not write in English with the misunderstanding that all different ideas and thoughts should be mixed together in a single sentence. . Different thoughts and different statements require their own sentences. .

Yes, the words "locates", "opposite" and "different" are not the right choice. There's also a punctuation error. See if you can find it. ;) I'm not sure if the last word was really what you meant: http://www.thefreedictionary.com/exacting http://www.thefreedictionary.com/exciting