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阅读材料：
Genetic modification, a process used to change an organism’s genes and hence its characteristics, is not being used to improve trees. Through genetic modification, it is possible to create trees that produce more fruit, grow faster, or withstand adverse conditions. Planting genetically modified trees on a large scale promises to bring a number of benefits.
First, genetically modified trees are designed to be hardier than nature trees; that it, they are more likely to survive than their unmodified counterparts. In Hawaii, for example, a new pest-resistant species of papaya tree has been developed in response to ring-spot virus infections that have repeatedly damaged the native papaya-tree population. Planting the genetically modified papayas has largely put an end to the ring-spot problem.
Moreover, genetically modified trees promise to bring a number of economic benefits to those who grow them. Genetically modified trees tend to grow faster, give greater yields – of food, fruit, or other products – and be hardier. This allows tree farmers to get faster and greater returns on their farming investment and save on pesticides as well.
Finally, the use of genetically modified trees can prevent overexploitation of wild trees. Because of the growing demand for firewood or building timber, many forests around the world are being cut down faster than they can be replaced. Introducing genetically modified trees – designed for fast growth and high yield in given geographic conditions – would satisfy the demand for wood in many of those areas and save the endangered native trees, which often include unique or rare species.
听力材料：
听力材料：
Sure, there is benefit to planting genetically modified trees, but are these trees really as great as they first sound? When you examine the subjects closely, there are some serious problems and causes associated with the using of genetic modified trees.
当然，种植基因改良树木是有好处的，但是真的有利到可以作为首选作物吗?当你仔细审视这些理由的时候，就会发现基因改良树木会带来一些严重的问题。
First, genetically modified trees may be resistant to one particular condition, but it doesn’t necessarily ensure their survival. You see: a typical non-modified tree population is genetically diverse. That means that for most threatening conditions, for climate, insects, and pests, whatever, there will be at least some individual trees of any given species tree that are resistant. So, even if the most of one kind of tree were killed, those few resistant ones will survive and ensure the survival of that species of tree. But, genetically modified trees are genetically much more uniform, so if there is supposed to an environmental challenge they have not been designed for, they will all die. So, if the climate changes or new pest engages in, the genetically modified trees will likely be completely wagged out.
首先，基因改良树木可能对某种特定问题有抵抗力，但是这却不足以保证它们的生存。你看，非基因改良的树木种群是具有基因多样性的。这就意味着无论何种树木，即便是在遭遇极端气候灾害或者虫害的情况下，都至少有部分个体对灾害有抵抗能力。所以，即便种群中的大多数都死亡了，那么少数有抵抗力的存活下来也能保证这个种群的延续。但是对于基因改良树木基因是一直的，所以当他们受到他们基因设计里不能低于的环境挑战时，他们会全部死亡。所以，当气候发生变化或者有新的害虫出现，那么基因改良树木就将全部死亡。
That is the second point. There are hidden causes associated with the growing genetically modified trees. You see, the company that genetically modified tree can charge tree farmers much more for its seeds than unmodified tree seeds would cost. Also, after you’ve grown the tree, you can not just collect the seeds and plant the new tree for free. By law, you have to pay the company every time you plant.
现在说第二点。在基因改良树木的生长过程中伴随着一些隐含问题。你看，公司都是以高于天然种子很多的价格向农民出售基因改良树木种子的。同时，你现在不能再每年收获之后收集种子，然后来年免费再种了。因为根据法律规定，你每年都必须向种子公司支付费用。
And finally, genetically modified trees might actually cause even more damage to the local wild trees. You see, genetically modified trees often grow more aggressively than natural trees do. And genetically modified trees are typically planted among natural trees. As a result, the genetically modified trees out compete the native trees for resources: sunlight, soil nutrition and water. Eventually, crowd out the nature trees.
我的：
The reading material makes the point that genetic modified trees can bring people a lot of benefits. In contrast, the listening material insists that although there are some benefits, genetically modified trees can also bring serious consequences.
First, the writer discusses that genetically modified trees are more likely to survive because they are designed to be hardier the nature trees. The lecture, however, hold a different view that as most of the genetically modified trees have uniform genes, they may all die in a particular condition such as a severe climate while nature trees have at least a few can survive because of the various genes.
Second, the author states that genetically modified trees can bring a number of economic benefits to those who grow them because they yields more food. On the contrary, the professor shows that the hide cost of planting these trees will be higher because farmers will be charged more for seeds and farmers can not collect the seeds of these trees to plant them again.
Third, the speaker refutes the viewpoint showed in the passage the use of genetically modified trees can prevent overexploitation of wild trees. The speaker says that genetically modified trees will damage the local trees because they will compete resources with nature trees when they are planted among them. As a result, they will crowd out nature trees.
求各位好心人批改，留下宝贵滴意见吧~~~~(>_<)~~~~ 真的不想再跟托福耗下去了。。。
ps：有近期想要互评、共同进步的小伙伴们没啊 求互评5篇~~~
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发表于 2014-3-3 22:33:05
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