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Now listen to a part of lecture on the topic you just read about.
现在来听一段有关你刚刚读到的话题的演讲。
Sure, there are some benefits to plant genetically modified trees, but, are these trees really as great as they first sound?
当然，种植转基因的树木有一些好处，但是，这些树木真的像它们开始听起来那么好吗？
When you examine the subject closely, there are some serious problems and costs associated with using genetically modified trees.
当你仔细检查这个主题时，有一些与转基因树木有关的严重的问题和花费。
First, genetically modified trees may be resistant to one particular condition.
首先，转基因树木也许会对一种特殊的环境有抵抗力。
But that doesn't necessarily ensure their survival.
但那不能保证它们的存活。
You see, a typical non-modified tree population is genetically diverse.
你看，一个典型的非转基因树种是基因多样化的。
That means that for most threatening conditions, for climate, insects and other pests, whatever,
那意味着对于大多数危险的环境，如气候、昆虫和其它害虫，不管什么，
there will be at least some individual trees of any given species of tree that are resistant.
无论哪个树种至少会有一些个体树木是有抵抗力的。
So even if most of one kind of tree are killed, those few resistant ones will survive and ensure the survival of that species of tree.
所以即使一种树的大部分被杀死了，那些少数有抵抗力的会存活下来并保证该树种的存活。
But genetically modified trees are genetically much more uniform.
但是转基因树木基因上更统一。
So if they're exposed to an environmental challenge they haven't been designed for, they'll all die.
所以如果它们暴露在一个它们没有为其而设计的环境挑战里，它们都会死。
So if the climate changes, or a new pest invades the area, the genetically modified trees will likely be completely wiped out.
所以如果气候变化了，或者一个新的害虫入侵该地区，转基因树木就可能会全部被消灭。
Now as to the second point, there are hidden costs associated with growing genetically modified trees.
现在关于第二点，种植转基因树木有着与其有关的隐藏消费。
You see, the company that genetically modify the tree tends to charge tree farmers much more for its seeds than unmodified tree seeds would cost.
你看，从基因上改变树木的公司常常为树种收树农更多的钱，比起非转基因的树种。
Also, after you've grown the tree, you can't just collect the seeds and plant the new tree for free.
而且，在你种了树之后，你不能仅仅收集种子免费种植新树。
By law, you have to pay the company every time you plant.
法律上，你每次种植的时候必须付钱给公司。
And finally, genetically-modified trees might actually cause even more damage to the local wild trees.
最后，转基因树木也许真的会引起对当地的野生树木带来更多的伤害。
You see, genetically modified trees often grow more aggressively than natural trees do.
你看，转基因树木通常比自然树木的生长更快速。
And, genetically modified trees are typically planted among natural trees.
而且，转基因树木通常是种植在自然树木中间的。
As a result, the genetically modified trees out-compete the native trees for resources, sunlight, soil nutrients, and water, eventually crowding out the natural trees.
所以，转基因树木在资源--阳光、土壤营养和水上超过了原生树木，最终排挤自然树木。
