Is writing the article required writing skills with advance english level?

For me yes because they are must very good in English.

Advance English writing skill certainly would give you a A+ opportunity to get your articles to be accepted. But that is not a problem. None of us are perfect here. I do what we do best to make it work though. I hope that you will get more of your articles to be accepted too.

yes to a certain point. they may have changed it because it fit better into what they wanted.

Some writing sites do require writers of advance level, but there are also some sites that do accept even beginners. What is important is that you are able to express yourself in writing, with correct grammar. You can try bukisa and triond. They accept almost everything you submit.

writing an article does not need specific advanced writing skills but the grammar must be appropriate and the content should not be mundane. when ever you write an article, don't post it at once and open it again with a fresh mind after some time( from 6 hours atleast) and when you open it again you will not believe that you will be able to revamp it completely and after 2-3 three reviews the article is ready to be posted. use a spell check always available in ms-word and you can increase your vocabulary so that you do not fumble while writing. and remember there is never too late... all the best.....

Yes, in the sense that most of the writing sites want to publish a high quality article that will attract others. To do so, they will emphasize at advanced vocabulary, other than interesting plot or story line. However, I think the availability of advanced vocabulary in your article is not the most important factor that determine their acceptance. In my opinion, a good "inner sense" and accuracy of the contents in the article play a greater role in determining their choice.

Most writing sites don't require advanced levels of English. But they do require basic correct grammar. Judging from your discussion, you haven't reached that level yet. That's not meant to be an insult. I realize that if English isn't your native language, you're going to have a harder time getting it right. Just keep working at it. I really admire people who are willing to write in a foreign language. I had two years of French in school, and I'll probably never be able to write anything readable in French.

It depends on the subject of the article, since educational ones need to be formed in a more linguistically advanced manner. I suggest you read such articles often so your skills can improve and in the meantime, practice as much as you can. If you feel like this type of expression does not suit you, prefer to compose less formal articles about simpler subjects, like entertainment, personal, how-to, etc.