對于雅思閱讀來說，雅思聽力的主題句是非常重要的，因為同學們能夠把握住雅思閱讀的中心思想，那么接下來就和51出國留學網(wǎng)來看看雅思閱讀如何把握主題句？
主題句的位置：
根據(jù)對劍4到劍12文章的分析，段落第一句是主題句的情況多達65%，約10%的段落是第二句為主題句，另有約5%的段落最后一句為主題句。當然也有找不出明顯主題句的段落，這部分約占20%。所以閱讀文章時，我們需要從每段的第一句開始，按照以下原則來確定主題句，從而概括出段落大意。
段落第一句是主題句，通常具有以下特征：
1、首句有概括性的詞，如：
The sense of vision is developed to different degrees in different en species studied at close quarters underwater — specifically a grey whale calf in captivity for a year， and free-ranging right whales and humpback whales studied and filmed off Argentina and Hawaii — have obviously tracked objects with vision underwater， and they can apparently see moderately well both in water and in air. However， the position of the eyes so restricts the field of vision in baleen whales that they probably do not have stereoscopic vision.
—劍4 Test 1 Passage 2 Paragraph 3
上述例子中，different degrees就是有概括性的詞，整段都圍繞著“不同鯨魚的視覺差異”展開。
由于主題句要統(tǒng)領整個段落，一般無過多的細節(jié)，故而句子較短。類似的情況還可以在劍4 Test 2 Passage 1 Paragraph 1和 劍5 Test1 Passage 3 Paragraph 2 見到。
2、首句為“人名+賓語從句”的格式，大概率上也可判定為主題句，如：
Earlier this year， Sergio Pellis of Lethbridge University， Canada， reported that there is a strong positive link between brain size and playfulness among mammals in general. Comparing measurements for fifteen orders of mammals， he and his team found larger brains （for a given body size） are linked to greater playfulness. The converse was also found to be true. Robert Barton of Durham University believes that， because large brains are more sensitive to developmental stimuli than smaller brains， they require more play to help mould them for adulthood.‘I concluded it＇s to do with learning， and with the importance of environmental data to the brain during development.＇ he says.
—劍4 Test 2 Passage 3 Paragraph E
劍6 Test 2 Passage 1 Paragraph A，也是類似的情況。若第一句不太明顯，不足以斷定是否為主題句，可快速地看一下第二句。首句后緊跟著例子或解釋，也可坐實首句是主題句。如：
But volcanoes are not very predictable. That is because geological time is not like human time. During quiet periods， volcanoes cap themselves with their own lava by forming a powerful cone from the molten rocks slopping over the rim of the crater； later the lava cools slowly into a huge， hard， stable plug which blocks any further eruption until the pressure below becomes irresistible. In the case of Mount Pinatubo， this took 600 years.
—劍4 Test 3 Passage 2 Paragraph D1
上述例子中，第二句是對第一句的解釋。還有一種類似的情況，第二句由for example開頭的，像劍4 Test 1 Passage 1 Paragraph 1和劍4 Test 4Passage 1 Paragraph 8，也能坐實第一句是主題句。
3、首句提出了問題，如：
Why do people reject the language of their parents？ It begins with a crisis of confidence， when a small community finds itself alongside a larger， wealthier society， says Nicholas Ostler， of Britain＇s Foundation for Endangered Languages， in Bath. ＇People lose faith in their culture，＇ he says. ＇When the next generation reaches their teens， they might not want to be induced into the old traditions.’
—劍4 Test 2 Passage 1 Paragraph 4
哪些情況不是主題句？
如果段落第一句具有以下特征，則不是主題句：第一句只是承接上一段，沒有講新的觀點/事物，如：
Here we have two radically different explanations for why so many teacher-subjects were willing to forgo their sense of personal responsibility for the sake of an institutional authority figure. The problem for biologists， psychologists and anthropologists is to sort out which of these two polar explanations is more plausible. This， in essence， is the problem of modern sociobiology-to discover the degree to which hard-wired genetic programming dictates， or at least strongly biases， the interaction of animals and humans with their environment， that is their behaviour.
—劍5 Test 1 Passage 2 Paragraph I
此時就應該意識到這個首句僅僅起到承上啟下的作用，沒有概括段落的功能。雖然第一句沒有承接上段，但是有讓步的意味，也不適合做主題句。如
Identifying genetically talented individuals is only the first step. Michael Yessis， an emeritus professor of Sport Science at California State University at Fullerton， maintains that ‘genetics only determines about one third of what an athlete can do. But with the right training we can go much further with that one third than we＇ve been going.’Yessis believes that U.S runners， despite their impressive achievements， are ‘running on their genetics＇. By applying more specific methods， ＇they＇re going to go much faster＇. These methods include strength training that duplicates what they are doing in their running events as well as plyometrics， a technique pioneered in the former Soviet Union.
—劍4 Test 4 Passage 1 Paragraph 3
該句的“only the first step”就含有讓步的意味。另外，如果在緊接著的第二句話中，看到有however，but，instead等轉折詞或出現(xiàn)否定前一句話的詞，也說明第一句話不是主題句。詳見下面的例子：
There is a widespread belief that increasing wealth encourages people to live farther out where cars are the only viable transport. The example of European cities refutes that. They are often wealthier than their American counterparts but have not generated the same level of car use. In Stockholm， car use has actually fallen in recent years as the city has become larger and wealthier. A new study makes this point even more starkly. Developing cities in Asia， such as Jakarta and Bangkok， make more use of the car than wealthy Asian cities such as Tokyo and Singapore. In cities that developed later， the World Bank and Asia Development Bank discouraged the building of public transport and people have been force to rely on cars — creating the massive traffic jams that characterize those cities.
—劍6 Test 2 Passage 1 Paragraph C
若第二句具備“提及新觀點/事物且有概括性的詞”或“句中有轉折詞”的特征，基本上可判定為主題句，如：
Stories about the problems of tourism have become legion in the last few years. Yet it does not have to be a problem. Although tourism inevitably affects the region in which it takes place， the costs to these fragile environments and their local cultures can be minimized. Indeed， it can even be a vehicle for reinvigorating local cultures， as has happened with the Sherpas of Nepal＇s Khumbu Valley and in some Alpine villages. And a growing number of adventure tourism operators are trying to ensure that their activities benefit the local population and environment over the long term.
—劍5 Test 4 Passage 1 Paragraph C1
但是，如果第二句依然在講細節(jié)，或者第二句話與第一句構成并列的關系，說明第二句也不是主題句。此時，我們不要去看第三句，應該直接跳至段尾，看段落的最后一句話。
段落的最后一句，如果具備以下特征，則可以判定為主題句：1）該句有概括性的詞語；2）尾句與本段前面的其他句子形成“例子 — 總結”的關系，如：
All our subjects deemed the circle soft and the square hard. A full 94% ascribed happy to the circle， instead of sad. But other pairs revealed less agreement： 79% matched fast to slow and weak to strong， respectively. And only 51% linked deep to circle and shallow to square. When we tested four totally blind volunteers using the same list， we found that their choices closely resembled those made by the sighted subjects. One man， who had been blind since birth， scored extremely well. He made only one match differing from the consensus， assigning ＇far＇ to square and ＇near＇ to circle. In fact， only a small majority of sighted subject — 53% — had paired far and near to the opposite partners. Thus， we conclude that the blind interpret abstract shapes as sighted people do.
—劍4 Test 1 Passage 3 Paragraph 8
當然，也有可能該段落本身就沒有主題句。如果大家讀完了第一句、第二句和最后一句，都沒法找到主題句的話，就要自己動手概括段落大意了。大體說來，具備 “介紹背景”、“敘事性強”、“時間/年份多”等特征的段落會比較難找到主題句。
雅思閱讀