One question that is often asked about writing content on your website is how much should you have to rewrite articles, or news sources, that you find so that they are not considered duplicate.
This is actually difficult to answer, because you can rewrite a news source in all honesty and still find that sections of it are duplicate, especially if you copy the original source into a word document to begin editing from that.
If your final article contains any sequence of five or more words that are the same then you have not rewritten significantly enough. Simply changing the odd adjective in the middle of a sentence or adding two sentences together to create one long sentence isn’t sufficient. Your final article will still be duplicate content, will still get flagged up by Google and could very well result in your site being penalised.
You should never used sections of your source in your article. Always rewrite sentences, even short ones, in your own words. If you use quotes, remember to block quote them so they’re not picked up as duplicates.