托福阅读要略读文章的哪些成分呢？
第一，是标题，标题总共分为3类。A、 A and B; 还有限定条件下的A。
首先A这种标题，比如这篇的groundwater,这种标题一般都会首先对A进行介绍，什么是A，然后介绍特点或者源头之类的，这是一个规律。 那么顺便我们也来说一下另外两类标题的套路。
如果是A and B这样的文章标题，那么文章内的讨论对象就会有A和B两个对象，一般会进行比较。比如Applied arts and fine arts这篇文章，文章内就分别用了一段介绍applied arts和fine arts,介绍过程中进行了一些对比，最后进行了总结。
最后一类限定条件下的A的标题，比如ele...全部
第一，是标题，标题总共分为3类。A、 A and B; 还有限定条件下的A。
首先A这种标题，比如这篇的groundwater,这种标题一般都会首先对A进行介绍，什么是A，然后介绍特点或者源头之类的，这是一个规律。
那么顺便我们也来说一下另外两类标题的套路。
如果是A and B这样的文章标题，那么文章内的讨论对象就会有A和B两个对象，一般会进行比较。比如Applied arts and fine arts这篇文章，文章内就分别用了一段介绍applied arts和fine arts,介绍过程中进行了一些对比，最后进行了总结。
最后一类限定条件下的A的标题，比如electricity from wind这篇文章，已经限定好的话题，一般就会直接讲它的特点和来源等内容，不会再去介绍比如electricity是什么了。
第二，我们说可以通过小结题或者表格题获得文章的主要内容或者主要讨论对象类别。(可以从表格题获取信息是指：比如applied arts and fine arts这篇文章的小结题题目是让我们归类哪些说的是applied arts特征，另外一些是fine arts特征，那么我们就可以知道这篇文章的主要讨论对象是fine arts and applied arts)
第三，文章开头结尾。
托福阅读文章都是一些科学类的说明文，科学类说明文就有一个不变的规律，文章必然是会存在总结的。常见的文章结构有：总分总，总分，和分总。把握文章总结也可以帮助获取文章主要内容。
第四，每段的段首和段尾。
尤其是段首特别需要我们引起注意。托福阅读文章每段的主要内容一般都在段首出现。段首不一定是说100%都在每段第一句就出现这段的TS，但是绝大多数文章每段TS一般都在每段前2句内会出现。其次，也存在在句尾出现这段TS的情况。
比如先说一个例子，再下总结句子。那之后的这句总结句才是这段的TS。
接着我们看一个具体例子：
Petroleum Resources
【1】Petroleum, consisting of crude oil and natural gas, seems to originate from organic matter in marine sediment。
石油是由原油和天然气组成。
//Microscopic organisms settle to the seafloor and accumulate in marine mud。 The organic matter may partially decompose, using up the dissolved oxygen in the sediment。
As soon as the oxygen is gone, decay stops and the remaining organic matter is preserved。
【2】Continued sedimentation—the process of deposits’ settling on the sea bottom—buries the organic matter and subjects it to higher temperatures and pressures, which convert the organic matter to oil and gas。
持续的沉积——堆积物沉积到海底的过程将有机物埋在海底使之受到海底温度、高压的影响，最终转变成石油和天然气。
As muddy sediments are pressed together, the gas and small droplets of oil may be squeezed out of the mud and may move into sandy layers nearby。
Over long periods of time (millions of years), accumulations of gas and oil can collect in the sandy layers。
Both oil and gas are less dense than water, so they generally tend to rise upward through water-saturated rock and sediment。
【3】Oil pools are valuable underground accumulations of oil, and oil fields are regions underlain by one or more oil pools。
When an oil pool or field has been discovered, wells are drilled into the ground。 油床是宝贵的地下石油积聚处，而油田是被一个或多个油藏覆盖区域。
Permanent towers, called derricks, used to be built to handle the long sections of drilling pipe。
Now portable drilling machines are set up and are then dismantled and removed。 When the well reaches a pool, oil usually rises up the well because of its density difference with water beneath it or because of the pressure of expanding gas trapped above it。
Although this rise of oil is almost always carefully controlled today, spouts of oil, or gushers, were common in the past。
Gas pressure gradually dies out, and oil is pumped from the well。 Water or steam may be pumped down adjacent wells to help push the oil out。
At a refinery, the crude oil from underground is separated into natural gas, gasoline, kerosene, and various oils。
Petrochemicals such as dyes, fertilizer, and plastic are also manufactured from the petroleum。
【4】As oil becomes increasingly difficult to find, the search for it is extended into more-hostile environments。
随着石油越来越难以找到，石油勘探已经开始到更恶劣的环境中进行。
The development of the oil field on the North Slope of Alaska and the construction of the Alaska pipeline are examples of the great expense and difficulty involved in new oil discoveries。
Offshore drilling platforms extend the search for oil to the ocean’s continental shelves—those gently sloping submarine regions at the edges of the continents。
More than one-quarter of the world’s oil and almost one-fifth of the world’s natural gas come from offshore, even though offshore drilling is six to seven times more expensive than drilling on land。
A significant part of this oil and gas comes from under the North Sea between Great Britain and Norway。
【5】Of course, there is far more oil underground than can be recovered。 当然，地下还能发现更多的石油。
It may be in a pool too small or too far from a potential market to justify the expense of drilling。
Some oil lies under regions where drilling is forbidden, such as national parks orother public lands。
Even given the best extraction techniques, only about 30 to 40percent of the oil in a given pool can be brought to the surface。
The rest is far too difficult to extract and has to remain underground。
【6】Moreover, getting petroleum out of the ground and from under the sea and to the consumer can create environmental problems anywhere along the line。
此外，从地下和海底开采石油并运送到消费者的途中的任何地方都会产生环境问题。
Pipelines carrying oil can be broken by faults or landslides, causing serious oil spills。
Spillage from huge oil-carrying cargo ships, called tankers, involved in collisions or accidental groundings (such as the one off Alaska in 1989) can create oil slicks at sea。
Offshore platforms may also lose oil, creating oil slicks that drift ashore and foul the beaches, harming the environment。
Sometimes, the ground at an oil field may subsideas oil is removed。 The Wilmington field near Long Beach, California, has subsided ninemeters in 50 years; protective barriers have had to be built to prevent seawater fromflooding the area。
Finally, the refining and burning of petroleum and its products can cause air pollution。 Advancing technology and strict laws, however, are helping control some of these adverse environmental effects。
首先我们也先来略读这篇文章。标题Petroleum Resources，讲的是石油资源，接着我们看小结题总结句“Petroleum” is a broad term that includes both crude oil and natural gas。
说石油是一个广泛的定义，包括原油和天然气。接着我们看开头结尾和每段TS。
第一段：介绍了石油由原油和天然气组成。石油来源：海底沉积物中的有机物质。海底沉积过程。
第二段TS：沉积过程怎么样产生石油。
第三段TS：提到了储存石油的模式：油床和油田。
第四段TS：随着石油越来越难以找到，石油勘探已经开始到更恶劣的环境中进行。
第五段TS：当然，地下还能发现更多的石油。
第六段TS：石油开采和运送过程中会产生环境问题。
总结一下，这篇文章的结构就是首先说石油包括什么。然后石油怎么形成的。然后以油床和油田的形式存在。接着说到现在石油越来越难找，已经扩展到比较难开采的一些地方。然后提到当然地底下还是存在挺多石油的。
最后提到石油开采运输过程中会造成污染。
Directions: An introductory sentence for a brief summary of the passage is provided below。
Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage。
Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage。
This question is worth 2 points。
“Petroleum” is a broad term that includes both crude oil and natural gas。
●Petroleum formation is the…
●The difficulty of finding…
●Petroleum extraction can…
Answer choices
○Petroleum formation is the result of biological as well as chemical activity。
○The difficulty of finding adequate sources of oil on land has resulted in a greater number of offshore drilling sites。
○Petroleum extraction can have a negative impact on the environment。
○Petroleum tends to rise to the surface, since it is lower in density than water。
(第二段细节)
○Current methods of petroleum extraction enable oil producers to recover about half of the world’s petroleum reserves。
(现在的石油开采技术可以使油recover世界石油储蓄的一半，未提及)
○Accidents involving oil tankers occur when tankers run into shore reefs or collide with other vessels。
(oil tanker和岸礁触碰造成油泄漏，未提及)
小结题，首先我们要知道小结题的要求：区分主干和细节，而我们要选的是文章的主干内容，基本上也就是文章结构内容了。接着我来看这个例子。选项A说石油形成是个生物化学的活动，这个就是第一第二段，石油是如何形成的。
选项B 体现的就是第四段的TS。选项C 就是最后一段的TS。我们发现这都是我们略读时候的文章结构部分。而我们继续看选项D 石油密度比水小，会慢慢上升到水面，这个是第二段石油形成的细节内容。不选。
而选项EF都是文章中没有提到的东西，所以更加不能是主干内容了。
所以我们可以发现略读文章对于文章小结题的作用还是很有帮助的，大家可以在平时训练中，试试这种方法。收起
