托福阅读目前一篇10题，需要18分钟内完成。其中耗费时间比较多的是文章的第10题----六个答案中选择正确的三个段落大意。这道概括题是综合了前面文章的内容，对段落大意是否正确进行判断选择。主要难点在于做到最后，文章内容记不清楚，无法判断选项内容的对错。对此，我们需要一些有效的方法，帮助大家有效地记住段落的内容，从而正确地判断选项描述的段落大意正确与否。这其中，还会涉及一些内容与原文符合，但是却并不属于段落大意的选项，这类选项一般描述的是文章中的细节信息。

细节信息，按照其内容，可以划分为三大类：文章中的细节，文章段落中的分论点以及文章中的一些实验内容。比如下列tpo-1中的段落：

There is still no universally agreed-on explanation for why there should be such a dramatic cessation of tree growth at the upper timberline. Various environmental factors may play a role. Too much snow, for example, can smother trees, and avalanches and snow creep can damage or destroy them. Late-lying snow reduces the effective growing season to the point where seedlings cannot establish themselves. Wind velocity also increases with altitude and may cause serious stress for trees, as is made evident by the deformed shapes at high altitudes. Some scientists have proposed that the presence of increasing levels of ultraviolet light with elevation may play a role, while browsing and grazing animals like the ibex may be another contributing factor. Probably the most important environmental factor is temperature, for if the growing season is too short and temperatures are too low, tree shoots and buds cannot mature sufficiently to survive the winter months.(TPO1-3)

在该文本中，段首2句是总起句，表达段落的总观点。第三句开始就是总起句中提及的“various environmental factors”的具体例子，一共有5个例子，其中最后一个例子temperature，根据文中内容，可能是造成“dramatic cessation of tree growth”的最重要的原因。这5个例子，都是文章中的细节，不可以作为段落大意。下面来看一下选项：

A. There is no agreement among scientists as to exactly why plant growth is sharply different above and below the upper timberline.

B. The temperature at the upper timberline is probably more important in preventing tree growth than factors such as the amount of snowfall or the force of winds.

C. High levels of ultraviolet light most likely play a greater role in determining tree growth at the upper timberline than do grazing animals such as the ibex.

正确的段落大意是A选项。C选项内容错误，因为temperature才是最重要的因素。B选项内容符合原文，但是它属于细节内容，并不能概括文章段落大意。所以排除之后，正确答案是A选项：关于林木线上下区域树木生长方式的不同的原因没有统一的解释。这三个答案中，比较容易选错的是B选项，毕竟它内容符合原文。所以在判断段意的过程中，大家还要注意排除细节内容。

希望这篇对于段落大意错误选项的排除方法，能给大家阅读练习一些帮助。祝大家早日取得满意的托福成绩，加油！