Genetic modification, a process used to change an organism’s genes and hence its characteristics, is now 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 harder than nature trees; that is, they are more likely to survive than their unmodified counterparts. In Hawaii, for example, a new pest-resistant species of papaya trees 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 farmer 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 and 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.


  Sure, there are some benefits to plant genetically modified trees, but, are these trees as really great as they first sound? When you examine the subject firstly, there are some serious problems and costs associated with genetically modified trees.

  First, genetically modified trees may be resistant to one particular condition. But that doesn’t necessarily ensure their survival. You see, a typical non modified trees’ population is genetically diverse. That means that for most threatening conditions, or climate, whatever, there will be at least some individual tress of any given species of tree that are resistant. So even if most of one kind of trees are killed, those few resistant tress will survive and ensure the survival of that species of tree. But genetically modified trees are genetically much more uniform. So if they’re exposed to an environmental challenge they have not been designed for, they all die. So if the climate changes, the genetically modified trees will likely to be completely wiped out.

  Now as to the second point, they’re hidden costs associated with genetically modified trees. You see, the company that genetically modify the tree can charge tree farmers more for its seeds than un- genetically modified trees would cost. Also, as you’ve grown the tree, you can’t just collect the seeds and plant the new tree for free. By law, you have to pay the company every time you plant.

  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 outcompete the native trees for resources, sunlight, soil, nutrients, and water, eventually crowding out the natural trees.


  Reading Passage

  Main points: Genetic modification on large scale will bring benefits.

  Sub point 1: Can be completely wiped out by certain environment.

  Sub point 2: Modified trees are economically better.

  Sub point 3: Modified trees grow fast and save wild trees.


  Attitude: Against. (Serious problem and associated cost.)

  Sub Point 1: There are effective ways to stop mussels in today’s knowledge

  Sub Point 2: Hidden costs associated like seeds.

  Sub Point 3: Do more damage to wild trees. Grow so fast and outcompete the wild tree.



  Paragraph 1

  The lecturer points out three different shortcomings of genetically modified trees. In the aspects of adaptation, economic lucrativeness, and environmental value, they never present overwhelming advantages compared with natural trees. This means the points made in the reading are partial and biased.


  (Listening passage后文提到用L代替)

  (Reading passage后文用R代替)




  Paragraph 2

  First, genetic modification doesn’t necessarily make a natural tree more resistant to environmental adversities. Although genetic modification may allow a species to manifest certain strengths in specific conditions, as the reading indicates, the new type lacks the genetic diversity of a natural species. Thanks to the marginal differences between individual trees, there can always be some survivors among natural species following a large interruption like climate change or pest invasion. But such changes may cause the distinction of a genetically modified species for their unification in characteristics, decreasing their overall survivability in many cases.




  此段为总分结构,陈列证据十分对称,Although but句型很好的列举了相对立的观点和证据。最后证明R之前的论点不可取。

  Paragraph 3

  Second, tree farmers don’t get guaranteed economic benefits if they plant genetically new strains. Companies that develop new plants always charge farmers higher prices for artificially improved seeds, and receive money from farmers each time farmers grow that same plant. Such laws and company policies can deprive farmers of any economic gain mentioned in the reading passage.





  Paragraph 4

  Third, genetically modified trees don’t promise to protect wild trees. In fact, since they can grow faster with fewer resources, they are more ecologically invasive than normal trees. Normally, they are able to outpace and stifle the growth of natural trees by using the available natural resources like sunshine, water and soil. It’s far from the idealistic situation described in the reading.






  1、 逻辑结构




  1. In the aspects of adaptation, economic lucrativeness, and environmental value, they never present overwhelming advantages compared with natural trees.

  In the aspects of (对于A,B,C这几个面来说), they never (他们从未,证明,呈现某论点)

  Adaptation: 适应


  Lucrativeness: 有利可图的


  2. Distinction: 区别,特征,个性

  There is a distinction between what he says and what he does.

  3. Deprive: 剥夺,免去


  We have no right to deprive their life.