Scholars, writers and teachers in the modern academic community have strong feelings about acknowledging the use of another person's ideas. In the English-speaking world, the term plagiarism is used to label the practice of not giving credit for the source of one's ideas. Simply stated, plagiarism is "the wrongful appropriation or purloining, and publication as one's own of the ideas, or the expression of ideas of another."　　1.　　The penalties for plagiarism vary from situation to situation. In many universities, the punishment may range from failure in a particular course to expulsion from the university. In the literary world, where writers are protected from plagiarism by international copyright laws, the penalty may range from a small fine to imprisonment and a ruined career. Protelars and writers, through the copyright laws and through the social pressures of the academic and literary communities, is a relatively recent concept. Such social pressures and copyright laws require writers to give scrupulous attention to documentation of their sources.　　2.　　Students, as inexperienced scholars themselves, must avoid various types of plagiarism by being self-critical in their use of other scholars' ideas and by giving appropriate credit for the source of borrowed ideas and words, otherwise dire consequences may occur. There are at least three classifications of plagiarism as it is revealed in students' inexactness in identifying sources properly.　　They are plagiarism by accident, by ignorance, and by intention.　　3.　　Plagiarism by accident, or oversight, sometimes is the result of the writer's inability to decide or remember where the idea came from. He may have read it long ago, heard it in a lecture since forgotten, or acquired it second-hand or third-hand from discussions with colleagues. He may also have difficulty in deciding whether the idea is such common knowledge that no reference to the original source is needed. Although this type of plagiarism must be guarded against, it is the least serious and, if lessons learned, can be exempt from being severely punished.　　4.　　Plagiarism through ignorance is simply a way of saying that inexperienced writers often do not know how or when to acknowledge their sources. The techniques for documentation-note-taking, quoting, footnoting, listing bibliography —are easily learned and can prevent the writer from making unknowing mistakes or omissions in his references. Although 'there is no copyright in news, or in ideas, only in the expression of them," the writer cannot plead ignorance when his sources for ideas are challenged.　　5.　　The most serious kind of academic thievery is plagiarism by intention. The writer, limited by his laziness and dullness, copies the thoughts and language of others and claims them for his own. He not only steals, he tries to deceive the reader into believing the ideas are original. Such words as immoral, dishonest, offensive, and despicable are used to describe the practice of plagiarism by intention.　　The opposite of plagiarism is acknowledgement. All mature and trustworthy writers make use of the ideas of others but they are careful to acknowledge their indebtedness to their sources. Students, as developing scholars, writers, teachers, and professional leaders, should recognize and assume their responsibility to document all sources from which language and thoughts are borrowed. Other members of the profession will not only respect the scholarship, they will admire the humility and honesty. [A] What to do as a student?　　[B] Various definitions of plagiarism　　[C] Ideas should always be sourced　　[D] Ignorance can be forgiven　　[E] Plagiarism is equivalent to theft　　[F] The consequences of plagiarism一、 二、 三、 四、 五、