托福閱讀文章題材眾多，而其中說明文是比較高頻的一種文章題材。由于說明文大多涉及到一些對大部分考生來說比較枯燥的內容，考生往往不太喜歡多做練習因此解題思路方面也常有欠缺。下面小編就為大家結合實例分析托福閱讀說明文題材，從文章結構開始學習解題思路。

托福閱讀說明文怎么看懂？

一般而言，托福閱讀中的說明文會說明某個現象，文章的第一段是：介紹背景及引出下文;之后的主體段，結構也很清晰：主旨句Topic sentence + 解釋句Explain + 舉例子Examples + 總結句Summary。 其實跟我們高考語文有異曲同工之妙。下面來看實例解析：

The Roman Army's Impact on Britain（選自TPO-19）

In the wake of the Roman Empire's conquest of Britain in the first century A.D., a large number of troops stayed in the new province, and these troops had a considerable impact on Britain with their camps, fortifications, and participation in the local economy. Assessing the impact of the army on the civilian population starts from the realization that the soldiers were always unevenly distributed across the country. Areas rapidly incorporated into the empire were not long affected by the military. Where the army remained stationed, its presence was much more influential. The imposition of a military base involved the requisition of native lands for both the fort and the territory needed to feed and exercise the soldiers' animals. The imposition of military rule also robbed local leaders of opportunities to participate in local government, so social development was stunted and the seeds of disaffection sown. This then meant that the military had to remain to suppress rebellion and organize government.

these troops had a considerable impact on Britain，也就是第一句說的是羅馬軍隊對英國有影響。這句話相當于對題目的闡述，交代了文章的整個大背景。 之后2～4句其實交代前提，開始具體的說開，要估算軍隊對平民的影響首先要了解一個事實：士兵不是平均分布的。那既然不是平均分布，肯定是有多有少的。所以，第三句接著說了有些地方士兵少：很快融入帝國的區域;第四句說有些地方士兵多影響大：軍隊駐扎的地方。第5～7句說回重點，也就是what，到底有哪些影響：軍營先要征地;然后會搶走當地領導參與政府的機會;之后社會發展受阻，人民不滿而反抗，最后軍事鎮壓。

首段的第一句話，雖然句子很長，但其實只需要抓住結構層次進行分析就能找到閱讀重點。

所以總共7句話的段落，分層三個層次，主旨句+前提說明+重點闡述。事實上，段落第一句就完成了background+introduction雙重目的：英國被羅馬帝國征服+ 士兵的營地/防御工事以及參與當地經濟所造成的影響。

Economic exchange was clearly very important as the Roman army brought with it very substantial spending power. …… Such activities had a major effect on the local area, in particular with the construction of infrastructure such as roads, which improved access to remote areas.

第二段一開始就交代了經濟交換的影響：強大的購買力，以及幫助修建基礎設施。

Each soldier received his pay, but in regions without a developed economy there was initially little on which it could be spent. …… These settlements acted like small towns, becoming centers for the artisan and trading populations.

第三段還是在講經濟：剛來的時候士兵有錢沒地方花;最后軍隊駐扎地變成了小鎮。

The army also provided a mean of personal advancement for auxiliary soldiers recruited from the native peoples, as a man obtained hereditary Roman citizenship on retirement after service in an auxiliary regiment. …… By the later Roman period, frontier garrisons (groups of soldiers) were only rarely transferred, service in units became effectively hereditary, and forts were no longer populated or maintained at full strength.

第四段開始講另一個重大影響：當地人通過當兵獲得可繼承的羅馬公民地位。

This process of settling in as a community over several generations, combined with local recruitment, presumably accounts for the apparent stability of the British northern frontier in the later Roman period. It also explains why some of the forts continued in occupation long after Rome ceased to have any formal authority in Britain, at the beginning of the fifth century A.D. The circumstances that had allowed natives to become Romanized also led the self-sustaining military community of the frontier area to become effectively British.

第五段，做了個小總結，講這種融合過程及當地招募促進了北部邊境的穩定。

通過上文實例講解，相信大家對于托福閱讀說明文的基本結構和解題思路也有了一定了解。之后大家在通過一些練習加深對說明文的認識和解題方法，以后面對這類高頻閱讀文章類型就能順利解答確保得分了。