托福阅读TPO5-1原文及答案

　　14.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.(Prose Summary Question)

　　Plants need to absorb certain minerals from the soil in adequate quantities for normal growth and development.

　　Answer Choices

　　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 in 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.

　　本题解析：

　　正确答案应陈述文章主要内容----矿物缺乏与过剩对植物的负面影响，以及利用超聚植物对过量矿物质的清除。

　　1.文章第五、六段指出超聚植物能够积聚大量矿物质，因此可用来低成本清除受污染地区的重金属：“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”。1正确。

　　2.文章第四段指出，过量矿物质的存在同样威胁植物的生长：“While mineral deficiencies can limit the growth of plants, an overabundance of certain minerals can be toxic and can also limit growth”。2正确。

　　3.文章第二段指出，特定矿物质的缺乏会导致植物出现萎黄病，坏疽等症状，阻碍植物生长：“Mineral deficiencies can often be detected by specific symptoms such as chlorosis, necrosis, anthocyanin formation, stunted growth, and development of woody tissue in an herbaceous plant”。3正确。

　　4.属细节信息，未反应文章主要内容。4错误。

　　5.文章未提及关于“能抵抗低矿物浓度的植物促进养分回流(recycling nutrients back into depleted soils)”方面的内容。5错误。

　　6.文中第三段提出的水栽法是对矿物质缺乏进行研究的方法，它并不能治疗矿物质缺乏症。6错误。

　　正确答案：

　　1，2，3

　　l 段意及难句解析：

　　●第一段：

　　段意：

　　本段指出矿物质是植物生长必须的元素，而现代农业收割导致了许多土壤的矿物质缺乏。

　　难句分析：

　　1. In modern agriculture, mineral depletion of soils is a major concern, since harvesting crops interrupts the recycling of nutrients back to the soil.

　　短语：mineral depletion of soils：土壤的矿物质缺乏

　　recycling of nutrients：营养元素循环

　　释义：由于农业收割打乱了营养元素的循环，使其不能返回土壤内部，土壤的矿物质缺乏是现代农业发展中的一个主要问题。

　　●第二段：

　　段意：

　　本段列举了几种由取乏矿物质导致的植物疾病症状。

　　难句分析：

　　1. 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.

　　主干，mineral deficiencies can be detected by symptoms such as…

　　释义：矿物质缺乏通常可由以下症状判断得出，例如植物萎黄症(叶绿素匮乏导致的枝叶泛黄)，坏疽症(成片状坏死的植物)，花青素沉着(茎叶部分形成的深红色素)，植株矮小，以及木质状组织的生长。

　　2.Typically, older leaves are affected first as the phosphorus is mobilized to young growing tissue.

　　词汇：affected文中应理解为“受到病害侵袭”

　　as意为“因为”

　　释义：通常衰老枝叶先发病，因为磷大都积聚在新生组织处。

　　●第三段：

　　段意：

　　本段介绍了两种用于研究植物营养缺乏症的种植方法。

　　难句分析：

　　1. This technique allows researchers to create solutions that selectively omit certain nutrients and then observe the resulting effects on the plants.

　　分句：selectively omit certain nutrients：有选择地去除特定营养物质

　　主干：this technique allows researchers to create… and then observe…

　　释义：这种技术使得研究者们可以制造出有选择地去除了特定营养物质的溶液，并进而对植物的反应进行观察。

　　2. Hydroponics has applications beyond basic research, since it facilitates the growing of greenhouse vegetables during winter.

　　短语：beyond basic research：在基础研究之外的其他应用

　　释义：水栽法可以应用在基础研究之外的领域，因为它可以帮助冬季温室蔬菜的生长。