托福閱讀最後一道大題是六選三，即從六個選項中選取三個，加上給出的句子，合成對全文的概括。正確選項的特征是 "the most important ideas in the passage"，是文章的核心信息 ; 錯誤選項的典型特征是文章細節。下面以兩個題目分別來看如何判斷主旨信息和細節信息。
托福文章題目：MINERALS AND PLANTS
下面分別是沒段段首的信息：
Paragraph 1 Research has shown that certain minerals are required by plants for normal growth and development.
Paragraph 2 Mineral deficiencies can often be detected by specific symptoms such as chlorosis ( loss of chlorophyll resulting in yellow or white leaf issue ) , necrosis ( isolated dead patches ) , anthocyanin formation ( development of deep red pigmentation of leaves or stem ) , stunted growth, and development of woody tissue in an herbaceous plant.
Paragraph 3 Much of the research on nutrient deficiencies is based on growing plants hydroponically, that is, in soilless liquid nutrient solutions.
Paragraph 4 While mineral deficiencies can limit the growth of plants, an overabundance of certain minerals can be toxic and can also limit growth.
Paragraph 5 Scientists have known for some time that certain plants, called hyper accumulators, can concentrate minerals at levels a hundredfold or greater than normal.
Paragraph 6 Only recently have investigators considered using these plants to clean up soil and waste sites that have been contaminated by toxic levels of heavy metals - an environmentally friendly approach known as phytoremediation.
題目：
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 answer choices 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.
Plants need to absorb certain minerals from the soil in adequate quantities for normal growth and development.
1. Some plants are able to accumulate extremely high levels of certain minerals and thus can be used to clean up soils contaminated with toxic levels of these minerals.
2. Though beneficial with lower levels, high levels of salts, other minerals, and heavy metals can be harmful to plants.
3. When plants do not absorb sufficient amounts of essential minerals, characteristic abnormalities result.
4. Because high concentrations of sodium chloride and other salts limit growth in most plants, much research has been done in an effort to develop salt-tolerant agricultural crops.
5. Some plants can tolerate comparatively low levels of certain minerals, but such plants are of little use for recycling nutrients back into depleted soils.
6. Mineral deficiencies in many plants can be cured by misting their roots with a nutrient solution or by transferring the plants to a soilless nutrient solution.
正確選項是 123。不難發現，選項 1 對應第 5 和 6 段 ; 選項 2 對應第 4 段 ; 選項 3 對應第 2 段。這是因為，所謂的文章主要信息，其實就是某一段或幾段的主旨信息。因此，如果有的選項不確定，可以回到文中把每段的主旨信息找到，作為判斷的依據。
除瞭選出正確選項外，還要擅長排除錯誤選項。常見的錯誤選項是文章提到的細節信息。那麼細節信息的特征是什麼 ? 先看例子。
托福文章題目：APPLIED ARTS AND FINE ARTS
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.
This passage discusses fundamental differences between applied-art objects and fine-art objects.
Answer Choices
○ Applied-art objects fulfill functions, such as containing or sheltering, and objects with the same function have similar characteristics because they are constrained by their purpose.
○ It is easy to recognize that Shang Dynasty vases are different from Inca vases.
○ Fine-art objects are not functional, so they are limited only by the properties of the materials used.
○ Renaissance sculptors learned to use iron braces to strengthen the internal structures of bronze statues.
○ In the twentieth century, fine artists and applied artists became more similar to one another in their attitudes toward their materials.
○ In all periods, fine artists tend to challenge the physical limitations of their materials while applied artists tend to cooperate with the physical properties of their materials.
錯誤選項為 245. 它們共同的特點是：細節信息，具體體現在：選項 2 裡的 Shang Dynasty vases, 選項 4 的 Renaissance sculptors, 選項 5 裡的 in the twentieth century 和 similar。這些細節信息的具體特征是：人名、地名、數字、年代等等。尤其當這些信息出現在句子主幹處時，要格外當心 !
以上就是小編為同學們整理的托福閱讀主旨題如何判斷主旨與細節的具體實例以及內容，希望能夠幫助到大傢！
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