You warm hearted man help me correct my composition,please!

The MP3
Has it ever happened to you? Have you ever traveled a long monotonous distance by train, where the compartments are stuffy and cramped, and then you regretted that you had not taken the Walkman with you—which at least could take your mind off the journey of boredom. When you actually take one with you, are you not bothered to take it out from your traveling bag—simply because it is not convenient to be taken ,and more likely to be smashed when you are on moving. People who are wealthy and have spare money for buying a MP3 needn’t despair when they are caught in such situations (and a lot of people do). Fortunately for them, modern electronic industry has produced a kind of sound device called MP3 which is used for playing audio files, and its size merely as small as that of a thumb.
MP3 is actually an able play-sound(可播放声音的) magnetic storage. You can store all sorts files in it through a computer, and all audio records can be played on it.
Some of my classmates have the MP3. A MP3 can be use many occasions : not only when needed to store some files, but when you have to kill with something relaxing the boredom time for instance experiencing a long uncomforting travel, walking along, or even when you are suffering a terrible tedious lecture in such situation MP3 acts as a perfect earplug. For few industrious students, just as my roommate Zhang Hua, often use it to play all sorts English recording. Every day, downloading the VOA from the internet, Zhang Hua listen them in every fragmentary time available—rest intervals between two classes, on the way to canteen, and even during her relieving nature time.
It becomes apparent that the MP3 is increasingly playing a role of importance. with the improvement of technology and the increasing of production, function of a MP3 is becoming more powerful, the quality more stable, and the price dropping down.. So, for me, the chances that I be able to buy one MP3 are not remote any longer. I have set up my mind of having a MP3 as soon as its price drops at its rock bottom, its power achieves its peak.

[Tdol]

Has it ever happened to you?- I'd change this to 'Has the following ever happened to you?'
you had not taken the Walkman with you- your Walkman
mind off the journey of boredom- mind off the boredom of the journey
are you not bothered to take it out- you can't be bothered to take it out
because it is not convenient to be taken- because it is not convenient (delte 'to be taken')
more likely- likely (delete 'more')
for buying a MP3- to buy an MP3
and a lot of people do- a lot of people are
modern electronic industry- today's electronics industry
and its size merely as small as that of a thumb- the size of a thumb
an able play-sound(可播放声音的) magnetic storage- I don't understand what you mean here
all sorts files in it- all kinds of files on it
have the MP3- have an MP3
A MP3 - An MP3
have to kill with something relaxing the boredom time- have time to kill
or instance experiencing a long uncomforting travel- on a long uncomfortable journey, for instance
just as my roommate Zhang Hua- like my roommate
all sorts English recording- all sorts of English recordings
downloading the VOA- after downloading the VOA
Zhang Hua listen them- listens to them on every possible\occasion
even during her relieving nature time- even when relieving herself
It becomes apparent- It is becoming apparent
playing a role of importance- playing an impiortant role
function of a MP3 is- the functions of an MP3 are
and the price dropping down.- and the prices are falling
that I be able- that I will be able
are not remote any longer- are no longer remote
set up my mind of having a MP3- set my mind on having an MP3
as soon as its price drops at its rock bottom- as soon as the prices are at rock bottom
its power achieves its peak- this doesn't fit in the sentence; I'd just delete it