【正确答案】 A

【答案解析】[听力原文]
Librarian: Good afternoon students. As most of you are already aware, when writing assignments one needs to cite their sources. The importance of this cannot be emphasised enough and so in today's tutorial we will be looking at how and why we need to provide references. So firstly let's start by explaining what citing, referencing and bibliography means as I can already see some looks of confusion from some of you. The Oxford Advanced Learner's Dictionary states that citing means to speak or write the exact words from a book, an author, etc within your text. According to the Cambridge Dictionary, bibliography means a list of the books and articles that have been used by someone when writing a particular book or article, whereas a reference, according to the Harvard Citation Guide, is the detailed description of the item from which you have obtained your information. Alright so why is this necessary?
Firstly, you need to distinguish work which is yours and that which is not. Secondly you need to show the sources from which you have based your work and finally to enable other researchers who read your work to know where they may go for further information. For these reasons it is very important that you cite material correctly. If you do not do so, it may cause you undue additional work in the future when you or another researcher needs to do some follow-up work.
There are many systems for citing sources. However, today we will look at one of the most popular ones, the Harvard Citation system. This will include how to cite sources within your text and then write references in your bibliography at the end of the report. Remember your sources are wide and varied these days and may include anything from traditional books to today's most sophisticated information gathering tool, the Internet.
So let's begin with citation. Within your text you only need to cite the surname and date of publication. The reader may then check the bibliography located at the end of the report for more detailed information. In this way the reader can see at a glance the authority used and how recent the information is. Please note when two authors have the same surname and have publications in the same year, initials are also used to avoid confusion. Secondly, if the author has two or more publications in the same year then lower case letters are used to distinguish them. And only the year is followed in brackets if the surname already occurs naturally in the text. If there are three or fewer authors, all three need to be stated in the text. However if there are four or more you only need to mention the first author and then write 'et al' after it or 'and others'.
Am I going too fast? You're getting all this down, aren't you?