在考生备考雅思阅读考试的时候，往往我们会去强调那些经典的老话题的重要性。但是，在如今这个改革创新成为潮流的时代环境下，考生要想取得满意的成绩，仅仅去关注老话题已经不能够保证考生取得自己满意的成绩了。本文将会就关注新话题的必要性以及常规新话题的形式作一个分析，以帮助考生更好的理解雅思阅读考试的新话题。
关注新话题的必要性
虽然部分“老话题”仍然在雅思考试中重复出现，但是新话题的不断推出是雅思考试必然的选择。
首先，老话题数目减少，新话题大量涌现。05年之前雅思阅读考试的文章背景变化很少，种类也不是很丰富，老话题占全年考察文章的比重较大。仅05年全年考察的雅思话题就有6成以上是老话题背景。但是自05年之后，新题的出现频率就逐步加快。到08年的时候，老话题在雅思全年考试中所占的比例下降至2成左右，新话题则如雨后春笋一般几乎出现在每一次的考试当中。甚至有一些场次的考试三篇文章都是新话题。如08年的1月10日、6月14日、7月26日等。
其次，超高频率出现的话题减少。05年之前，阅读文章背景的重复率比较高。拿04年的话题举个例子。“海底探测船”、“蝴蝶农场”、“纸币发展”、“钱币发展”等话题出现了2次：“欧洲森林保护”出现3次：“语言变迁”、“医疗保健”、“校园暴力”、“运动员”、“澳洲疗法”等等话题都出现了4次或更多。05年“运动与英国青少年健康”出现3次，而04年出现过的“海底探测船”在05年也是出现了3次之多。随着时间的推移，自06年起，虽然也还是会出现诸如“纸币发展”之类的老话题，但是这些老话题很少会像之前一样出现很多次。像04年那种4次之上的，已经几乎不可能会出现了。当然之前的某些超高频率的出现题目也因其典型性而入选剑桥系列，成为雅思考试的范例供广大考生研究行文结构及出题角度了。
从以上两点可以清楚的看出，一方面雅思考试老话题的数量在严重缩减，考生见到老话题的几率在降低；另一方面，即使出现了老话题，此话题在全年中的出现频率也不可能太高，基本都在两次以内。所以，雅思考试新题不断出现的步伐是坚定而不可阻挡的。
常见新话题的形式
作为一个成熟的语言水平测试系统，雅思考试的新话题当然也不会完全没有规律可循，在此，朗阁海外考试研究中心的老师将就外延扩大型及旧瓶新酒型这两大类常见的新话题形式进行特点分析并指出考生应对这两类新话题的方法。
外延扩大型
这种新题是在保留原有核心内容的基础上作一个新的延伸。总的来说，调整不算太大，即在原有的知识基础上再补充一些相关的信息。以环保节能型的新能源开发的话题为例。在07年12月8日出现的英国潮汐发电的文章，主要内容就是讲解潮汐发点的装置及相关内容。但是，在08年9月27日再次考察这一内容的时候，则是以“海洋发电”的形式出现，介绍了四种主要方法的海洋发电的方法。这样一来就要求考生在掌握潮汐发电内容的同时，对于其他海洋发电类型也有所了解才能应付相关的文章。
以下是摘自“维京百科”的关于潮汐发电及海洋热能发电的一些背景知识，
Tidal power, sometimes called tidal energy, is a form of hydropower that converts the energy of tides into electricity or other useful forms of power.
Although not yet widely used, tidal power has potential for future electricity generation. Tides are more predictable than wind energy and solar power. Historically, tide mills have been used, both in Europe and on the Atlantic coast of North America. The earliest occurrences date from the Middle Ages, or even from Roman times.
Tidal power can be classified into three main types:
Tidal stream systems make use of the kinetic energy of moving water to power turbines, in a similar way to windmills that use moving air. This method is gaining in popularity because of the lower cost and lower ecological impact compared to barrages.The largest tidal energy is the bay of Fundy
Barrages make use of the potential energy in the difference in height （or head） between high and low tides. Barrages are essentially dams across the full width of a tidal estuary, and suffer from very high civil infrastructure costs, a worldwide shortage of viable sites, and environmental issues.
Tidal lagoons, are similar to barrages, but can be constructed as self contained structures, not fully across an estuary, and are claimed to incur much lower cost and impact overall. Furthermore they can be configured to generate continuously which is not the case with barrages.
Ocean thermal energy conversion （OTEC or OTE） is hydro energy conversion system which uses the temperature difference that exists between deep and shallow waters to run a heat engine. As with any heat engine, the greatest efficiency and power is produced with the largest temperature difference. This temperature difference generally increases with decreasing latitude, i.e. near the equator, in the tropics. Historically, the main technical challenge of OTEC was to generate significant amounts of power, efficiently, from this very small temperature ratio. Changes in efficiency of heat exchange in modern designs allow performance approaching the theoretical maximum efficiency.
The Earth's oceans are continually heated by the sun and cover nearly 70% of the Earth's surface; this temperature difference contains a vast amount of solar energy which can potentially be harnessed for human use. If this extraction could be made cost effective on a large scale, it could provide a source of renewable energy needed to deal with energy shortages, and other energy problems. The total energy available is one or two orders of magnitude higher than other ocean energy options such as wave power, but the small magnitude of the temperature difference makes energy extraction comparatively difficult and expensive, due to low thermal efficiency. Earlier OTEC systems had an overall efficiency of only 1 to 3% （the theoretical maximum efficiency lies between 6 and 7%）. Current designs under review will operate closer to the theoretical maximum efficiency. The energy carrier, seawater, is free, although it has an access cost associated with the pumping materials and pump energy costs. Although an OTEC plant operates at a low overall efficiency, it can be configured to operate continuously as a Base load power generation system. Any thorough Cost-benefit analysis should include these factors to provide an accurate assessment of performance, efficiency, operational and construction costs and returns on investment.
The concept of a heat engine is very common in thermodynamics engineering, and much of the energy used by humans passes through a heat engine. A heat engine is a thermodynamic device placed between a high temperature reservoir and a low temperature reservoir. As heat flows from one to the other, the engine converts some of the heat energy to work energy. This principle is used in steam turbines and internal combustion engines, while refrigerators reverse the direction of flow of both the heat and work energy. Rather than using heat energy from the burning of fuel, OTEC power draws on temperature differences caused by the sun's warming of the ocean surface.
，雅思阅读关注新话题必要性