A few Chinese Sentences - Grammatically Correct?

[Ascendancy9]

中国是澳大利亚出口最多的贸易国家

世界上有四分之一的人在说中文

住在中国可以提高你的汉语水平

住在中国的时候可以产生跟中国生意人关系

I was wondering if those sentences are grammatically correct. Much appreciated!

[imron]

中国是澳大利亚出口最多的贸易国家

Offtopic: Grammar aside, what source is this from? According to current statistics from DFAT, Japan is number 1 for exports, and China is number 2. China is number 1 for imports though.

[Ascendancy9]

I actually just made it up. It's not an actual statistic. I just included it in a practice essay regarding the benefits of studying Chinese.

/Offtopic

Is the grammar ok though?

[againstwind]

中国是澳大利亚出口最多的贸易国家

Consider:

中国是澳大利亚的第一大出口国

世界上有四分之一的人在说中文

No problem.

住在中国可以提高你的汉语水平

No problem.

住在中国的时候可以产生跟中国生意人关系

consider:

住在中国的时候可以跟中国生意人（商人）建立联系

or

住在中国有助于与中国商人建立（良好的商务）关系

[Ascendancy9]

Great, thanks for your help!