各位大哥大姐,帮我解释一下英语短文,然后顺便回答几个问题,是英语高手的就进哈!

各位大哥大姐,帮我解释一下英语短文,然后顺便回答几个问题,是英语高手的就进哈!
There are more than 3,000 million people on the earth and about 2,500 languages.Of these languages only about twelve are used by more than 50 million people.Here are the names of some languages which have very wide use:Chinese,English,French,German,Japanese.etc.All these languages have more people speaking them today than ever before.A hundred and fifty years ago there were only about twenty million people who talked in English,for example.Now there are at least two hundred and fifty million,and there may be many,many more
Many students in China are learning English.Some of these students are small children.Others are teenagers.Many are adults.Some learn at school,other study by themselves.A few learn English language over the radio,on television,or in films.One must work hard to learn another language.
Why do all these people want to learn English It is difficult to answer that question.Many boys and girls learn English at school because it is one of their subjects.They study their own language and math and Enlish.Some people learn English because at college or university some of their books are in English.Other people learn English because they want to read newspaper and magazines in English.
1.What must one do if he wants to learn another language well?
2.What does the sentence “It is difficult to answer the question.”mean?
3.What does "their own language"mean?
4.What's the Chinese of "study by themselves"?

翻译：
世界上有超过30亿人和大约2500中语言.其中仅有12种使用人数超过5000万.以下这些语言被极其广泛的使用：汉语、英语、法语、德语、日语等等.现在人们使用这些语言超过以往任何时候.例如：在150年前,仅有大概2千万人使用英语交谈.而现在至少有两亿五千万人,而且会越来越多.
许多中国学生在学习英语.有些学生是小孩子.还有些是青少年.多数是成年人.一些在课堂上学习,一些自学.有少数通过收音机、电视或者看电影去学习英语.学习别的语言必须非常努力.
为什么这些都想学英语?回答这个问题很难.许多男生女生学英语,因为这是他们的课程.他们学习汉语、数学和英语……有些人学习英语是因为他们在大学用的书是英文的.另一些人学英语因为他们想阅读英文的报纸和杂志.
1.如果想学好一门外语应该怎么做
2.句子“难以回答这个问题”是什么意思
3.这个“他们自己的语言”是什么意思
4.“study by themselves”用汉语怎么说
回答：
1.work hard
2.People learn English for many different reasons
3.It means Chinese
4.自学
这么长你也叫它短文.拜托,别开玩笑了,手都抽筋了.早点睡觉吧,不用这么刻苦...o(∩_∩)o