Three acts of plagiarism:
1) Not citing a quotation or borrowed ideas
2) Not putting borrowed language in quotation marks
3) Not putting summaries and paraphrases in your own words
Examples
A) “Joe Blow was a happy man, who often walked down the road whistling and singing” (Scrivener, 2001, p.33).
B) Joe Blow was a happy man who often walked down the road whistling and singing (Scrivener, 2001, p.33).
C) According to Scrivener (2001), Joe appeared happy and enjoyed whistling and singing to himself (p.33).
D) Joe Blow was a merry man who often strolled down the path singing and whistling.
References
Scrivener, J. (2001). Joe Blow: his life and times. New York: Random House.
These examples are taken from:
Lipson, C. (2004). Doing honest work in college. Chicago: University of Chicago Press.
Example website: http://www.albertmohler.com/2006/04/07/from-traitor-to-hero-responding-to-the-gospel-of-judas/