What must one do if he wants to learn another language well?还有What does "their own language"mean

题目

What must one do if he wants to learn another language well?还有What does "their own language"mean
还有 What's the Chinese of "study by themselves"?

答案

What's the Chinese of "study by themselves意思是："study by themselves“中文是什么意思,用汉语怎么说?
What does "their own language"mean意思：their own language是什么意思?
What must one do if he wants to learn another language well意思：如果一个人想掌握另外一种语言,那么他必须做什么?