在同學們托福英語學習的過程當中，都會遇到一只攔路虎——長難句，考試也不例外。托福考試模擬了美國大學一年級或二年級公共課教材的難度，旨在衡量非英語國家的學生是否有足夠的能力接受美國的教育。在當中，長難句的考點是句子簡化題。長難句在文章中被突出顯示，要求考生選出一個最反映原句核心信息的選項。(Which of the sentences below best expresses the essential information in the highlighted sentence in the paragraph? Incorrect choices change the meaning in important ways or leave out essential information.)這類句子不僅單詞難度高，而且句子結構非常復雜。要求考生有較好的語法背景或者語感良好。句子簡化題的長難句最典型的情況就是對比對照，下面我們舉例加以分析。

TPO1-Groundwater

原句：If the pores are large, the water in them will exist as d rops too heavy for surface tension to hold, and it will drain away; but if the pores are small enough, the water in them will exist as thin films, too light to overcome the force of surface tension holding them in place; then the water will be firmly held.

以分號為界，整個句子劃分為兩個層次。兩句中間的But 是重要信號，明確的告訴我們前后文意相反。

參考譯文：如果小孔很大，水會以水滴的形式存在，水滴過重表面張力無法支撐，從而水會流走;但是，如果小孔足夠的小，水就會以薄膜的形式存在，這樣就會很輕而不會克服表面張力，從而水會牢固的留下。

A. Surface tension is not strong enough to retain drops of water in rocks with large pores but it strong enough to hold on to thin films of water in rocks with small pores.

B. Water in rocks is held in place by large pores and drains away from small size pores through surface tension.

C. Small pores and large pores both interact with surface tension to determine whether a rock will hold water as heavy drops or as a thin film.

D. If the force of surface tension is too weak to hold water in place as heavy drops, the water will continue to be held firmly in place as a thin film when large pores exist.

下面我們來對比選項，A 選項完全重復了原句的含義，

A 為正確答案。

B 選項：如果巖石的孔足夠大就會留下水，而小孔則會讓水流走。乍一看選項出現了對比對照，但是仔細閱讀后發現B 的內容和原句正好相反，這是托福典型迷惑選項：交叉匹配。

C 選項：大孔和小孔都會和表面張力發生作用，從而決定巖石中留下的水是水滴還是薄膜。明顯的篡改，刪除C 選項。

D 在大孔當中，如果表面張力太弱無法留住大水滴，水會繼續以薄膜的形式牢牢地附著。D 選項已經把原句改的面目全非了。

在長難句分析中，對比對照句句的核心信息就是兩者的不同點，只要抓住了核心特征，句子簡化題就迎刃而解了。祝同學們考試順利!