2.1.2The logic of academic English paragraphs
Conventionally, writing needs to be arranged deductively (演繹法) as shown in Figure 22. Deduction is an inference method from generalized knowledge (main idea) to case observations (supports, cases or examples). It is a common way of reasoning in scientific study and academic paper writing. Deduction from supports to cases can be further realized by the specific methods of paragraph constructions: definition, illustration, time, space, comparison and contrast, etc. as exemplified in Sample 2.
Figure 22An outline of conventional inference in academic paragraphs
[Sample 2]
Chronic stress is most common among people in the workplace, especially among women. Scientists studying stress in the workplace say many working women are under severe stress because of the pressures of work, marriage and children. Some experts say that pressure can cause a chemical imbalance in the brain that can lead to depression. More than thirtymillion American women suffer from depression. These problems are linked to their stressfilled lives and constant hurrying. (黃一瑜、閔楠、殷紅梅，2008)
[Analysis]
This paragraph is developed in a deductive way, with main idea conveyed by the topic sentence “Chronic stress is most common among people in the workplace, especially among women”. This main idea is supported by a subidea, i.e. the second sentence, “many working women are under severe stress because of the pressures of work, marriage and children.” And then it is further illustrated by detailed examples from experts opinions and examples.
2.2Academic English sentential conventions
in medical paragraphs
2.2.1The topic sentence and its function in journal article paragraphs
Generally, the topic sentence is the first sentence as in Samples 1 and 2. It may also be found in the middle or at the end of a paragraph as in Sample 3. A topic sentence summarizes the main idea of a paragraph. It tells the readers what to expect in the paragraph. Usually it is the most general and most important statement in the paragraph. The topic sentence does the following tasks: it names the topic in the paragraph,
telling the readers what the paragraph is about (e.g. claimed...lives\/strengths); it contains a controlling idea that commits the paragraph to a specific aspect of the topic (e.g. hundreds of thousands of\/several).
[Sample 3]
Yellow fever most likely originated in Africa and was imported into the Americas in the 1600s. It claimed hundreds of thousands of lives in the 18th and 19th centuries. The Philadelphia yellow fever epidemic of 1973, for example, killed approximately 10% of the citys population and prompted the federal government to flee the city. In 1881, Cuban epidemiologist Carlos Finlay proposed that yellow fever was a mosquito borne infection. The U.S. Army physician Walter Reed and a Yellow Fever Commission verified that fact in 1900. Subsequently, mosquitocontrol efforts and better sanitation practices virtually eliminated yellow fever from the United States and other nonendemic areas of the America, although sporadic outbreaks of varying magnitude continued to occur in tropical regions where the disease was endemic. (Paules & Fauci, 2017)
[Analysis]
In this sample, the second sentence is the topic sentence, with the controlling ideas of thousands of casualties in the 18th and 19th centuries. All the other sentences are supporting sentences, explaining the two periods in the two centuries. And they are all relevant to the main idea.
2.2.2The requirements of topic sentence writing in medical journal article paragraphs
There are four requirements of topic sentence writing. First, a topic sentence is affirmative (肯定句), not interrogative (疑問句) or negative (否定句). Second, a topic sentence is an opinion, not a fact. It generally contains subjective words like injurious (有害的) or beneficial (有益的). Third, a good topic sentence has a controlling idea like “many talents”, “three effects”, “beneficial physically and mentally”. Last, a good topic sentence is neither too broad (e.g. Diabetes is effective or common) nor too narrow (e.g. Diabetes is caused by genetic factors.).
[Sample 4]
Diabetes is more common and has much larger effect on mortality in Mexico than in major highincome countries. By 60 to 74 years of age, approximately one quarter of the participants in the current study had received a medical diagnosis of diabetes, as compared with approximately 7% in the United Kingdom and approximately 15% in the United States at the time of our baseline survey, and even after adjustment for other risk factors, the rate of death from any cause between 35 and 74 years of age was approximately four times as high among participants with diabetes as among those without diabetes. In contrast, metaanalyses of prospective studies from mostly highincome countries showed that person with diabetes had less than twice the rate of death from any cause as those without diabetes.(The Emerging Risk Factors Collaboration, 2011)
[Analysis]
The paragraph begins with a topic sentence, the first sentence, and then gradually develops that statement into two main effects on mortality: “four times” and “less than twice”.
2.2.3Supporting sentences and their functions in medical journal article paragraphs
In a paragraph, sentences which are used to support the main idea of the whole paragraph are defined as supporting sentences. They provide data, evidence, or supporting explanation for the main idea. All the supporting sentences should be relevant to the topic sentence, or they fail to contribute to the main idea of the paragraph, leading to digression (跑題).
[Sample 5]
Our study has several important strengths. We have addressed the major limitations of previous studies by including more data sources and quantifying the prevalence of obesity among children.We also systematically evaluated the strength of evidence for the causal relationship between high BMI and health outcomes and included all BMIoutcome pairs for which sufficient evidence with respect to causal relationship was available. We used a beta distribution to characterize the distribution of BMI at the population level, a method that captures the proportion of the population with high BMI more accurately than other distributions. We used the best available evidence to determine the lowestrisk BMI. We quantified the burden across levels of development and estimated the contribution of demographic transition and epidemiologic transition to changes in BMIrelated burden. (The GBD 2015 Obesity Collaborators, 2017)
[Analysis]
In this sample, the first sentence is the topic sentence in the paragraph, with the controlling ideas of important strengths. All the following sentences are supporting sentences, explaining strengths in this study. And they are all relevant to the main idea.
2.2.4The concluding sentence and its function in medical journal article paragraphs
In western rhetoric tradition, a paragraph tends to have a natural conclusion by generalizing the main idea of the whole part. It is similar to the topic sentence in meaning but in a fresh way. Anyhow, a conclusion sentence cannot add new information to the paragraph, which will lead to failure of paragraph unity.
2.3Principal methods of paragraph construction
in academic English essays
2.3.1Definition
Writing often involves defining words or terms so that readers know exactly what you mean by them. Definitions are useful for explaining the meaning of a word or a term that readers may be unfamiliar with or may misunderstand.
Two types of definitions are useful in academic writing: simple definitions and extended definitions. A simple definition is one that can be stated in a few words—“Fitness, for example, is a state of physical health, resulting from exercise and proper nutrition.” An extended definition is longer, usually a paragraph or more, and can become the basis of a whole essay.
[Sample 6]
Rift Valley fever is an emerging mosquitoborne infection caused by Rift Valley fever virus
(genus Phlebovirus, family Bunyaviridae), with outbreaks in Africa and more recently also in the Arabian Peninsula. However, the virus has the potential to spread to other continents. The infection is characterized by a high casefatality rate in young animals and causes mass abortions in cattle, goats, and sheep. In human beings, Rift Valley fever presents in most cases as a mild illness with influenzalike symptoms. However, in 1%—3% of cases it progresses to a more severe haemorrhagic disease involving liver necrosis, ocular disease, internal and external haemorrhaging, and encephalitis, which could be lethal.
[Analysis]
A definition of an unfamiliar term typically starts with common and familiar terms. The term Rift Valley fever is first illustrated with a general explanation and then with a series of details from animals to human beings. Words or phrases often used in definition include “characterized by”, “caused by”, “in most cases”, etc.
2.3.2Illustration
Illustration is used to explain statements or ideas via examples, and details, specific instances. It provides examples—details, particulars, and specific instances—to explain statements that we make. Connections for illustration generally involve “in case”, “illustration”, “instance”, “representative”, “sample”, “occurrence”, “in occurrence of”, “as representative of”, “for illustration\/instance”, “sample for”, etc.
[Sample 7]
GM foods are good for the environment. The damage to the environment that insecticides (殺蟲劑), such as DDT, bring about is well known. The use of synthetic fertilizers on farmland leads to the eutrophication (超營養作用) of rivers and lakes all over the world. GM foods use fewer pesticides, herbicides and fertilizers, and, therefore, cause less pollution.
[Analysis]
Sample 7 develops the central idea of the paragraph by using examples and contrast. The first sentence states the main idea, and the supporting sentences provide contrasting details of the fertilizers harms and of the GM foods benefits to the environment. The explanation lies in the examples in the underlined parts concerning various fertilizers.
2.3.3Development by time
Paragraph development in chronological order is called development by time. That is, all the events are arranged in the same order as they actually occurred. Chronological order presents ideas according to the time in which they occurred. It means that you begin with the very earliest and then progress to the most recent.
Table 21Words & phrases often used in time sequence
sequenceprogressionseriessuccession
evolutionadvancementsubsequencesequential
adjacentcyclicalpreviouslysubsequently
innovatein sequencein successionin evolution
in advancementin progressionin a subsequent wayin sequence of
[Sample 8]
The first cases of a new illness involving fever and rash that was deemed to have been caused by Zika virus (ZIKV) infection in Brazil were reported in 2014, and the presence of the virus was confirmed in April 2015. In October 2015, an unusual increase in the number of cases of microcephaly among newborn infants was reported in Brazil; this disorder was apparently linked to ZIKV infection. Here, we use routinely collected surveillance data and medical records to show how the spread of ZIKV in Brazil was associated with an increase in the incidence of GBS and microcephaly during 2015 and 2016. We also highlight the limitations of routinely collected data, which cannot yet explain, for example, why there were many fewer cases of microcephaly than expected in 2016. (Brouter et al., 2016)
[Analysis]
The excerpt develops ZIKV infection chronologically from 2014 to 2016. Time expressions serve as major transitional signals to link all the sentences together, as “in April 2015”, “In October 2015”, “during 2015 and 2016”, and “in 2016”.
2.3.4Development by space
Paragraph development by space is one of the commonest ways to arrange material. The physical appearance of someone or something usually calls for the organization of details into some kind of spatial relationship, (someone) from head to feet, (mountain) left to right, near to far, (building) outside to inside, etc.
Table 22Words & phrases often used in space sequence
next toon the opposite sideacrossto the left
to the rightin frontin backabove
belowbehindnearbybeyond
in the foregroundin the backgroundforeground to background
bottom to tophead to toe
[Sample 9]
The prevalence of both risk factors declined in all regions during the period. South Asia had
the largest drop in both the number and prevalence of children exposed to stunting or extreme poverty, followed by east Asia and the Pacific region. Accompanied by about a 16% increase in the population aged younger than 5 years in the region, subSaharan Africa had a rise in the number of children exposed to stunting and poverty, but the prevalence of the two risk factors also declined. SubSaharan Africa remained the region with the highest prevalence of children at risk in both years (Table 2). The findings were robust when the moderate poverty measure was used. (Lu et al., 2016)
[Analysis]
This part is organized by spatial order, “from South Asia”, “east Asia”, “the Pacific region”, and “to SubSaharan Africa”. The arrangement follows from the lowest to the highest prevalence of children at risk.
2.3.5Cause and effect
Cause and effect essays are concerned with why things happen (causes) and what happens as a result (effects). Cause and effect is a common method of organizing and discussing ideas.
Cause and effect paragraphs demonstrate the causal relationship between two sets of things. Trying to discover and reveal the causes or the effects of an event or action is one of the most common mental activities in our daily life. Therefore, the ability to clarify the causal relationship between two things is useful when we want to persuade or convince other people. An article may discuss both the causes and the effects of an event, but in a paragraph we analyze the causes or the effects rather than both.
Connections for causeeffect relationship are “in consequence”, “consequently”, “due to”, “thanks to”, “owing to”, “contributing to”, “in effect”, “hence”, “because of”, “result in”, “efficiently”, “effectively”, “in an effective way”, “so”, “is\/are due to”, “the consequence of”, “one effect of”, “this is because”, “as”, “the effect of”, “consequent (levels)”, “therefore”, “as a result”, “for this reason”, “thus”, “as a consequence”, etc.
[Sample 10]
Genetically Modified Foodthe Benefits and the Risks (excerpted)
(黃一瑜、閔楠、 殷紅梅，2008)
GM foods can fight malnutrition. In a world suffering from malnutrition, GM foods can answer the need for more nutritious food. To cite an example, Swiss researchers strove to create a rice strain that contains large amounts of betacarotene and iron to counteract vitamin A and iron deficiencies. Malnutrition can refer to both under nutrition and wrong nutrition. People in rich and developed countries may have more than enough food to eat but still not the proper nutrition necessary to keep them healthy.
GM foods are good for the environment. The damage to the environment that insecticides, such as DDT, bring about is well known. The use of synthetic fertilizers on farmland leads to the eutrophication of rivers and lakes all over the world. GM foods use fewer pesticides, herbicides and fertilizers, and, therefore, cause less pollution.