12 Science Research Writing Th e problem with using the passive in formal writing is that the agent (the person who performed the action of the verb) is oft en not mentioned in the sentence. In other words, we say that something was done or was identifi ed but we don't say 'by me' or 'by other researchers', so the reader may not know who did it or who identifi ed it. Th is can cause confusion and for that reason it is sometimes clearer to use a dummy subject (Th is article/ the present paper) in the Introduction rather than the 'agentless' passive (x is presented). Now look at the way the passive and dummy subject are used in the Introductions of your target articles. PARAGRAPHING Why is paragraphing important? Paragraphs are an important visual aid to eff ective reading and writing. Two common errors in paragraphing are clusters of short or single- sentence paragraphs, and paragraphs that are too long. Both errors will confuse readers and are signs of poorly-organised writing. To understand how paragraphing works, imagine that you have won a 24-hour trip to Paris. You have two options. Th e fi rst option is to fl y to Paris, get off the plane and walk around the city. If you take that option, a friend may ask you later if you saw the famous Louvre art gallery; you say: 'Well, no, I got lost and spent hours walking around the industrial area by mistake.' You show your mother the clothes you bought in Paris and she asks if you bought them in the famous Rue de la Paix shopping street, and you say, 'No, I bought them near my hotel. I didn't know where the big shopping area was.' You begin to realise that you wasted a lot of time and missed many important things. Th is article describes an algorithm for clustering sequences into index classes. Th e present paper presents a set of criteria for selecting such a component. let your reader know when you are referring to your own work. You can also use a 'dummy' subject to take the place of I or we:
Introduction — Grammar and Writing Skills 13 Th e second option is to take a short helicopter ride over Paris before you leave the airport. It's a diffi cult decision because you are impatient; you only have 24 hours and you don't want to waste time, but you do it anyway. Th e helicopter fl ies over Paris for half an hour in a grid pattern, aft er which you begin your tour of Paris. You fi nd a well-situated hotel, which you saw from the helicopter. You buy your clothes in the Rue de la Paix — which you saw from the helicopter. You visit the Louvre and you have lunch in one of the big parks near the centre ... which you saw from the helicopter. What is the connection between this and good paragraphing? Let's bring that idea to the skills of reading and writing. If you read the last page of a murder mystery before you fi nish the book, the rest of the story is less exciting — but you may fi nish the book faster. Th is is because you don't waste time wondering who the murderer is; you know it's the husband, so whenever his name is mentioned you concentrate and read carefully, but you don't bother to read the details about the other suspects. Th is enables you to read faster by giving you the confi dence to ignore things which you know are not relevant. Th e more you know about what you are reading, the faster and more eff ectively you read. So how can you fi nd out about a long article or chapter before reading it? Th e answer is to skim it quickly before you begin to read. Like the helicopter ride over Paris, skimming is done before reading, not instead of reading. Your aim when you skim through a text is to fi nd out quickly what it is about and where the various pieces of information are located so that you can read it faster and more confi dently. How do I skim effi ciently and quickly? Most of the instructions in the box on the next page tell you just to 'look at' or 'check' something. Skimming is a pre-reading technique and should be done very fast; if it takes more than a few minutes you're not skimming, you're reading. Skimming may help me read, but how does it help me to write? Look at number 6 in the box: LOOK QUICKLY AT THE FIRST SENTENCE OF EACH PARAGRAPH. A paragraph in academic writing oft en starts with a topic sentence, which gives the main idea of the paragraph, and tells the reader what the paragraph is about. Th e other sentences are related to