Any time you use someone else's words exactly you should quote them. It might just be two words or it could be two paragraphs of their work but you will need to quote them.
Different citation styles will dictate to you exactly how to do it, but at it's base you're simply putting "quotation marks" around the words you're borrowing.
For more information on citing correctly, check out our Libguide on citing.
To summarize is to take someone else's work and to greatly condense it while using your own words and expressions. You might summarize an entire book in a page, or maybe an article in a page. If you need to use distinctive phrases from their work, you can do that, just quote the phrase and cite the work.
When you summarize (and even when you don't quote them) you MUST CITE THE SOURCE that you are summarizing. Summarizing is an effective tool in a writer's toolbox but you must remember that any time you use someone else's words or ideas you need to give them credit.
For more information on citing correctly check out our Libguide on citing.
For more information on summarizing check out these resources:
Paraphrasing is similar to summarizing because it has you using your own words to restate someone else's work.
It differs from summarizing in that your paraphrase will be roughly the same length as the original, or a little shorter.
Remember as you paraphrase to ensure that your way of stating the material is sufficiently different in word choice and sentence stucture from the original, otherwise you will have plagiarized. If it makes sense to use something directly from the original just quote it and cite it.
Why paraphrase? Most people choose to paraphrase because it allows them to use a source's information without using its words. Perhaps the original's language or way of expressing itself is unimpressive. Maybe you don't want to break the flow of your own paper with a quotation and someone else's words. Maybe you've already quoted many times in your paper and you don't want to have still another.
Even when you paraphrase you must cite the original!
For more information on paraphrasing check out these links: