引用：
If your teacher finds part of your paper on PlagiarismChecker.com but you still want to say you didn't copy it, then try this: Calculate the probability that you would write exactly the same words as the author of a Web site.Assume that the English language has a vocabulary of 1000 words, which is really much smaller than it should be. (Hey - I'm trying to give you the benefit of the doubt!) The probability that you didn't copy from the Internet is
引用：
x = the number of words in the Web site that exactly match a phrase in your paper
c = the number of phrases on the Internet that are the same number of words as the phrase you wrote (assume that c=1,000,000,000,000,000 or 1015)
The math will show you the probability that you would write exactly the same words that someone else did without copying. The chance is very small. For a ten-word sentence, the probability that you didn't plagiarize would be about 0.000000000001%.
引用：
http://www.plagiarismchecker.com/copying-from-internet.php