托福综合写作优秀作文练习题：生物基因的改良

　　托福综合写作听力材料：

　　Sure, there is benefit to plantinggenetically modified trees, but are these trees really as great as they firstsound? When you examine the subjects closely, there are some serious problemsand 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 beresistant to one particular condition, but it doesn’t necessarily ensure theirsurvival. You see: a typical non-modified tree population is genetically diverse.That means that for most threatening conditions, for climate, insects, andpests, whatever, there will be at least some individual trees of any givenspecies tree that are resistant. So, even if the most of one kind of tree werekilled, those few resistant ones will survive and ensure the survival of thatspecies of tree. But, genetically modified trees are genetically much moreuniform, so if there is supposed to an environmental challenge they have notbeen designed for, they will all die. So, if the climate changes or new pestengages in, the genetically modified trees will likely be completely waggedout.

　　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 hiddencauses associated with the growing genetically modified trees. You see, thecompany that genetically modified tree can charge tree farmers much more forits seeds than unmodified tree seeds would cost. Also, after you’ve grown thetree, you cannot just collect the seeds and plant the new tree for free. Bylaw, 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 evenmore damage to the local wild trees. You see, genetically modified trees oftengrow more aggressively than natural trees do. And genetically modified treesare typically planted among natural trees. As a result, the genetically modifiedtrees out compete the native trees for resources: sunlight, soil nutrition andwater. Eventually, crowd out the nature trees.

　　最后，基因改良树木可能会对本土野生树木造成更多的损害。你看，基因改良树木相对于天然树木生长的更为迅猛。而且，基因改良树木一般来说跟天然树木是共同生长的。那么结果就是，基因改良树木会抢占天然树木的资源，诸如阳光、土壤和水等。慢慢地，基因改良树木就会挤走天然树木。

　　托福综合写作听力笔记：

　　Main point: 优点之中都存在问题

　　Sub point one: 如果遇到不能抵御的病虫害，可能会全部死亡

　　Sub point two: 会增加农民的成本，因为种子公司有权每年收费

　　Sub point three: 会损害天然森林，因为会争夺自然资源

　　托福综合写作范文(仅供参考)：

　　In the lecture, the professor claims thatalthough they may be some benefit, planting genetic modified trees will bringpotential problems and costs. She totally opposes the three statements made inthe reading passage.

　　Firstly, the professor indicates thatgenetic modified trees may resistant, but this cannot guarantee their survival.She points out that in fact the unity of genes within genetic modified plant willincrease their likelihood to wipe out when there is some threatening situation.The professor counters the claim made by the reading passage.

　　Secondly, the professor opposes the readingpassage by pointing out there is hidden cost behind modification trees. Thoughgenetic modification trees may provide more products or can save pesticide,their seeds are usually charged at a higher price. In addition, according tothe law, a farmer has to pay for the seed each time they plant the trees. Thiswill not bring any economic benefit mentioned in the reading passage.

　　Last but not least, the professor opposesthe statement that genetic modification trees will prevent overexploit of wildtrees. In fact, genetic modification trees tend to grow aggressively and can easilyexhaust the resource of normal trees. This will bring disastrous result for thelocal vegetation.