閱讀中非限制性定語從句真的不重要嗎？我們都知道，非限制性定語從句對先行詞起到了補充說明的作用，省略它句意仍然是完整的，正因如此，很多學生在處理閱讀中帶有非限制性定語從句的長難句時，常常對其視而不見，直奔主干，但是萬事萬物當然都不是絕對的啦，托福題目中，有些題目中恰恰考的就是非限制性定語從句這部分。

我們來看如下例題：
The principal seagoing ship used throughout the Middle Ages was the galley, a long, low ship fitted with sails but driven primarily by oars. The largest galleys had as many as 50 oarsmen. Since they had relatively shallow hulls, they were unstable when driven by sail or when on rough water; hence they were unsuitable for the voyage to the East. Even if they hugged the African coastline, they had little chance of surviving a crossing of the Indian Ocean. Shortly after 1400, shipbuilders began developing a new type of vessel properly designed to operate in rough, open water: the caravel. It had a wider and deeper hull than the galley and hence could carry more cargo; increased stability made it possible to add multiple masts and sails. In the largest caravels, two main masts held large square sails that provided the bulk of the thrust driving the ship forward, while a smaller forward mast held a triangular-shaped sail, called a lateen sail, which could be moved into a variety of positions to maneuver the ship.
According to paragraph 3, what did the lateen sail contribute to the caravel as a sailing ship?
?A.It provided stability for the front part of the ship.
?B.It made it possible for the hull to be wider and deeper.
?C.It added considerably to the speed of the wind-driven ship.
?D.It improved the capacity of the ship to be guided.
顯然，這是一道事實信息題，題目問lateen sail對caravel的功能是什么，直接可以定位到最后一句，可知lateen sail是一種三角帆，但對它的描繪就是最后的非限制性定語從句，可知它可以移動到不同位置控制帆船，對應D選項。所以這句話中非限制性定語從句就是解題關鍵。

接下來我們再看一道句子簡化題：
The explanation is that the Maya excavated depressions, or modified natural depressions, and then plugged up leaks in the karst by plastering the bottoms of the depressions in order to create reservoirs, which collected rain from large plastered catchment basins and stored it for use in the dry season.
Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.
?A.Southern Maya populations obtained the water they needed for the dry season by collecting and storing rainwater in sealed depressions.
?B.The Maya are credited with creating methods for modifying natural rainwater and storing it.
?C.Leaks in the karst caused difficulties in the creation of reservoirs, which were needed to store water for the dry season.
?D.Southern Mayans were more successful at collecting rain than storing it during dry seasons.
原句的essential information是瑪雅人做了三個動作，即excavated depression、modified natural depressions 和plugged up……為了create reservoirs，其后便是非限制性定語從句對reservoir進行補充說明，也就是reservoir的作用，即收集雨水以便干旱季節使用的，因此這句話中非限制性定語從句也是至關重要的，不可忽視，表達出瑪雅人是如何解決干旱季節的用水問題。

綜上，非限制性定語從句在文中的作用也要視語境分析，不可一概而論，因此還希望學生在后期的刷題中多多觀察多做總結。