Avoid plagiarizing.  Put ideas in your own words.

For example, here is a paragraph from an article by MacCoy, who writes:

Low concentrations at Diversion (range from 1 to 30 mg/L) reflect the sediment-trapping capability a the reservoirs upstream. The reduction in sediment load just downstream from reservoirs can lead to significant channel degradation and armoring of substrates (Wood and Armitage, 1997)  Also, impoundments tend to moderate high discharge downstream and, thereby, limit a river’s natural ability to flush out fine sediments and prevent armoring embeddedness.

If the student copies the paragraph without showing where the quotation begins and ends, this is plagiarism, even if the student cites the source:

Low concentrations at Diversion (range from 1 to 38 mg/L) reflect the sediment-trapping capability at the reservoirs upstream. The reduction in sediment load just downstream from reservoirs can lead to significant channel degradation and armoring of substrates. Also, impoundments tend to moderate high discharge downstream and, thereby, limit a river’s natural ability to flush out fine sediments and prevent armoring and embeddedness (MacCoy, 2004, p.21).  This is plagiarism. The text is exactly the same as MacCoy's text (except for the citation).  So the student is merely copying the author's words, and this is plagiarism.  In the US and Europe (and most other places), this sort of plagiarism is wrong, even illegal.  I cannot accept papers that are plagiarized. 

How do you fix it?  SHOW WHERE THE QUOTATION BEGINS AND ENDS WITH QUOTATION MARKS (or indent the long quotation):

" Low concentrations at Diversion (range from 1 to 38 mg/L) reflect the sediment-trapping capability at the reservoirs upstream. The reduction in sediment load just downstream from reservoirs can lead to significant channel degradation and armoring of substrates. Also, impoundments tend to moderate high discharge downstream and, thereby, limit a river’s natural ability to flush out fine sediments and prevent armoring and embeddedness " (MacCoy, 2004, p.21).

 Better still, you should paraphrase by change the wording (so it is not a quotation).   For example you could write:  According to MacCoy, the low concentrations of sediments below reservoirs show that they are able to trap sediments because they often decrease downstream discharge and so they reduce a river's ability to carry fine sediments (2004, p.21)  You don't need quotation marks here because you have changed the wording, but you still need to cite the source of the paraphrase.

With shorter quotations or sentences, you still need to cite quotations with quotation marks:

The student writes:  Thus, there is a large difference in suspended sediment concentration between the irrigation and nonirrigation seasons (MacCoy, 2004, p.23).

But MacCoy writes:  "However, there is a large difference in suspended sediment concentration between the irrigation and nonirrigation seasons."

So again the student has plagiarized MacCoy because he has only changed one word in the sentence.  To cite this correctly you should write:

Thus, "there is a large difference in suspended sediment concentration between the irrigation and nonirrigation seasons" (MacCoy, 2004, p.23).  Notice the quotation marks here.  You need to show when you are using an other person's words by showing where the quotation begins and ends.  Failing to do this is plagiarism, which is considered cheating.

 Turning plagiarized work is unacceptable.  You will receive a grade of 0 or F for plagiarized work.

NOTE:  In technical writing, authors usually paraphrase rather than quote.  Avoid quoting.  Avoid plagiarism by showing where quotations begin and end with quotation marks.

  Also see "What to cite"