I gave up learning English when I graduated from university. I think it's pity.
I have been working work for years. I realize now that English is very necessary.
If you can speak English you will be promoted, so you can do more things others can't do.
But, I am lost. I don't know how to pick up English again. I am looking for a teacher who can teaching me English.
I found that there is are so much many knowledge to memorize.
I will come overcome all difficulties.

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A couple of hints to remember: always start a new sentence with a capital letter; English or any particular language is a proper noun (the names of specific people, places, and things) and should be capitalized. 

Actually you have a good basis in English to start from;  I say that because I could understand what you meant even though it wasn't perfect.

If you can work to improve your English the investment of time should pay off.  It can seem overwhelming at first to think of all you need to learn but just take it one step at a time and you will get there.

If you need clarification about anything let me know.  Good luck! 

I have started reviewing english (please correct my message if you have time)

I gave up learning english when i graduated from university. I think it's a pity.
I have been worked for years when I realize that english is very neccesiry.
If you can speak english you will be promoted, because you can do more things others. 
But, I am lost. I don't how to pick up english again. I am looking for a teacher who will teach me english.
I found that there are so many things to memorize.
I will get over all the difficulties.