Plagiarism is a serious ethical offense in academics and in business. It is taking another's language and work without citing it and therefore claiming it as your own. The solution to plagiarism is to cite your sources. If someone says something perfectly, put the quotation in your work inside quotation marks and cite the source of the quotation (article, book, Web page, etc.). Paraphrasing should be cited as well, though it shouldn't be in quotation marks. This makes you not only ethical but well read.
Below is a list of paper and e-books that can answer your questions about correct English grammar.
Learning to write academically is a process that you will learn as you write papers and read scholarship. To get more help at CSUSB, make an appointment with The Writing Center (undergraduates) or The Graduate Writing Center (graduates). However, below you will find tips to learning the craft and links for more information.