一键复制
每个人都曾试图在平淡的学习、工作和生活中写一篇文章。写作是培养人的观察、联想、想象、思维和记忆的重要手段。范文怎么写才能发挥它最大的作用呢？下面是小编帮大家整理的优质范文，仅供参考，大家一起来看看吧。
四年级阅读理解专项训练免费篇一
- 英语阅读课教案 推荐度：
- 高考英语阅读常见高频单词 推荐度：
- 英语阅读高频单词高中 推荐度：
- 英语阅读理解课教学反思 推荐度：
- 转述句练习及答案 推荐度：
- 相关推荐
概括大意与完成句子
the importance of particular metals in the human diet has been realized within the past few decades， and the idea that geology might be related to health has been recognized for a number of elements such as iodine， zinc and selenium. for example， soils with low iodine contents produce crops， and animals deficient in iodine. a lack of iodine in the human diet leads to some serious diseases.
the ultimate source of metals within the human body is rocks， which weather into soil， gaining or losing some of their chemical constituents. the crops we eat selectively remove from the soil the elements that they require for growth. the water we drink contains trace elements leached from rock and soil. thus the geology and geochemistry of the environments have effects on the chemistry and health of plants， animals and people.
so far there is no data to suggest that people living on metal-rich soils experience a potential health hazard. the levels of metals within naturally contaminated soils are generally not high enough to cause serious health problems. living on metal-rich soils does not represent a health risk unless large quantities of soil are digested or metal-rich dust is inhaled. however， small children are particularly exposed to metal-rich topsoil in playgrounds and gardens. they are also the most likely ones to eat potentially dangerous metal-rich soil.
heavy metals are persistent; they do not break down to other chemicals in the environment. industrially polluted sites usually undergo intensive clean-up and rehabilitation because heavy metals are a health concern once they enter the food chain. some trace metals are alleged to cause cancer and are also known to cause poisoning.
in contrast， naturally contaminated soils have not been subject to risk assessment studies and rehabilitation measures， despite the fact that they frequently possess metal concentrations well above those of such polluted by humans and above environmental quality criteria.
there is a vital need to understand the potential risks and long-term health effects of living on naturally contaminated soils. future environmental investigations of naturally polluted soils should concentrate on the potential pathways of metals into the food chain and human body. geologists should be part of such studies as they can provide the essential background information on rock and soil chemistry as well as the chemical forms of heavy metal pollution.
a. no evidence to indicate bad effects of naturally contaminated soil
b. potential hazards of human contaminated soils
c. research on channels of heavy metals getting into human food chain
d. geology and health problems
e. rocks-the ultimate source of soil pollution
f. long- term health effects on children
1. paragraph 1
2. paragraph 3
3. paragraph 4
4. paragraph 6
a. industrially polluted soils
b. rock and soil chemistry
c. naturally polluted soils
d. the pathways of metals into the food chain
e. the element of iodine
f. the persistence of heavy metals
5. some serious diseases is connected with deficiency of ……
6. it is extremely necessary to study the long-term effects caused by living on ……
7. geologists are indispensable in the research project on geology and health due to their knowledge on……
8. industrially contaminated sites usually require a thorough clean-up due to ……
参考答案： dabcecbf
s("content_relate");【英语阅读练习】相关文章：
英语练习阅读03-19英语的阅读题练习06-26英语练习阅读技巧06-24英语阅读练习与讲义09-12英语阅读的提升与练习11-21关于英语阅读练习11-18英语阅读理解练习10-13《愉快地阅读》中考英语阅读练习07-03高考英语阅读表达练习02-21
