“端午节”前，质监部门对市场上的粽叶进行专项检查时，发现有些颜色翠绿的粽叶是用硫酸铜溶液浸泡的，人吃了用这种粽叶包的粽子，严重影响身体健康；但硫酸铜在农业上可用于配制农药．可见，化学是一把双刃剑，合理利用化学物质可以造福于人类，反之则会给人类带来危害．请你以塑料为例，谈谈使用塑料的利与弊（只答三点，必须体现利与弊两方面）．
对人类有利的一面：A、大部分塑料的抗腐蚀能力强，不与酸或碱发生反应；B．塑料的制造成本较低，而且耐用、防水；C．塑料容易被塑制成不同的形状；D．塑料一般不导热、不导电，是良好的绝缘体．
对人类不利的一面：A、回收利用废弃塑料时，分类十分困难，而且经济上不合算；B、有些塑料容易燃烧，燃烧时产生有毒气体；C．大部分塑料不会腐烂，也不能被细菌分解，容易造成“白色污染”；D．塑料是由石油炼制成的，石油资源是有限的．
故答案为：利：塑料成本低；耐用；防水；抗腐蚀等．
弊：浪费石油资源；易造成白色污染；难降解等．
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| Some personal characteristics play an important role in the development of one's intelligence. But people fail to realize the importance of training these factors in young people. The socalled nonintelligence factors'(非智力因素)include __1__ feelings, will, motivation, interests and habits. After a 30year followup study of 8000 males, American psychologists __2__ that the main cause of disparities in intelligence is not intelligence __3__, but nonintelligence factors including the desire to learn, will power and selfconfidence. __ 4__ people all know that one should have definite objectives, a strong will and good learning habits, quite a number of teachers and parents don't pay much attention to __5__ these factors. Some parents are greatly worried __6__ their children fail to do well in their studies. They blame either genetic factors, malnutrition(营养不良)or laziness, but they never take __7__ consideration these non-intelligence factors. At the same time, some teachers don't inquire into these reasons __8__ students do poorly. They simply give them more courses and exercises, or __9__ criticize or laugh at them. After all, these students lose self-confidence. Some of them just feel defeated and __10__ themselves up as hopeless. Others may go astray(迷途)because they are sick of learning. A __11__ of more than 1,000 middle school students in Shanghai showed that 46.5 per cent of them were __12__of learning because of examinations, 36.4 per cent lacked persistence, and consciousness and 10.3 per cent were sick of learning. It is clear __13__ the lack of improvement of nonintelligence factors has been a main obstacle(障碍) to __14__development in teenagers. It even causes an imbalance between physiological and __15__ development among a few students. If we don't start now to __16__ the improvement of nonintelligence factors, it will not only affect the development of the intelligence of teenagers, but also affect the__17__ of a whole generation. Some experts have put forward __18__ about how to improve students' nonintelligence factors. First, parents and teachers should __19__ understand teenage psychology. On this basis, they can help them to achieve the objectives of learning, __20__ their interests and toughening their willpower. | ||||
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