plagiarism...

Few days back I got back my introduction from my supervisor... The result from the scan state that my work consisted of 13.35% similarity with (include in print out 27 websites) articles from the internet. My expression at that moment was like O_O??!!??... I did my introduction by myself in my own words and the websites given I had not seen. Well, that's still alright I thought, there must be thousands of work outside on the internet. Finding something similar is not so surprising since my work contains a lot of facts. But still, 27 websites... and only for 13.35% of my work... *hmmm... these authors must have BLOODY COPIED every word from each other!!!...* *sigh* It's either I have to bend and alter facts, give a novel length explanation for something worth one sentence or use poor grammar in order to make it my own work... -_-"...