why 澳洲 have 澳洲沙漠 we havent?

What do you mean by 'we'? China? Hong Kong?

There is a Gobi desert (戈壁沙漠) in Mongolia, China! Most deserts are found in inland regions with low precipitation and dry climates, or they occur on the western sides of continents where the winds are off-shore. Hong Kong is such a small place and it has a tropical monsoon type of climate, so it is not possible for a desert to form in places like Hong Kong, unless global warming causes abrupt changes in global climates, which could be quite probable. So, start to conserve and protect the environment now!

2007-05-24 21:31:16 補充：
The driest continent on earth should be Antarctica.

Australia is the dryest continent in the world.