2023年12月25日发(作者：)
Unit 2 Hew Kinds of Food
Part 1
Teacher: Hi, everybody…how's it going? ... Good .…Has everyone turned in
their homework? All righty, then let's get started. IF you remember, last week
we were discussing some research in the area of genetics. Today, I'd like to talk
about something I'm sure you've all heard about-genetically modified or "GM"
food.
Genetically modified food is food--either a plant or animal--that has been
altered in the laboratory by scientists. The scientists take something from one
plant or animal, and add it to a different plant or animal to make it grow in a
different way. Today, we'll look at some of the benefits, and the possible risks
of genetically modified fond.
Let's start with a discussion of some of the benefits of GM food. Genetic
scientists are really trying to make food plants that are better than normal
plants, to make plants that are altered in ways that make the plant grow
better or taste better or be healthier to eat than normal plants.
One benefit is that genetically modified plants may need fewer pesticides than
normal plants. For example, there is a type of corn that is bad for
insects--when the insects eat the corn plant, they die. However, the corn
doesn't hurt people. This type of corn is beneficial because farmers use fewer
pesticides to grow the corn, and so there is less pollution in the environment.
Also the corn is less expensive because the farmers don't have to spend a lot
of money on pesticides. So, by using fewer pesticides, the corn is cheaper and
the environment is cleaner.
Another benefit of genetically modified plants is that they may grow better
than normal plants. One example is a type of genetically modified strawberry
that can grow in cold weather. These are better than normal strawberries
because farmers can plant the strawberries earlier in the spring and later in
the fall, when normal strawberries usually die. So, as a result, farmers can
grow many more strawberries than they used to. So that's another benefit
plants that grow better.
Finally, a third benefit is that many genetically modified plants stay fresh
longer after they are harvested. So, for example, there is a land of tomato that
stays fresh in the store for about two months, instead of one or two weeks.
This means that there is more time to get the food to the stores and that
stores have more rime to sell the food. Less food is thrown away and wasted.
So it's a great benefit to have food that stays fresh longer--and we can
consume more of the food we grow.
Part 2
Teacher: Now that we've looked at some of the benefit of genetically modified
plants, let's talk about the risks of growing this type of food. We don't really
know what the harmful effects are, but there are several things that people
ate worried about.
One risk is that the genetically modified plants may start to dominate the
other wild plants in the environment. This is a problem with some types of
tomatoes, for example. The new tomato plants are stronger than normal
plants, and because they are stronger and grow faster than the wild plants, the
genetically modified tomatoes may start to dominate the environment,
causing the wild plants to die. So having one plant dominate all the other
plants isn’t t good for the environment.
Another risk is that genetically modified plants will hurt wild animals and
insects in the environment. For example, the genetically modified corn 1
mentioned earlier has already caused this problem. Now some butterflies that
live near the corn are dying--butterflies that are good insects, and don't eat
the corn. It's possible that corn is killing the butterflies somehow, but we're
not sure. We just know that more butterflies are dying than normal. But
clearly there's a risk that genetically modified foods can hurt animals and
insects in the environment.
But probably the most important risk is that genetically modified food may be
harmful to the people who consume the food. The alterations in the plants
may cause serious problems for people--we just don't know. Scientists are
trying all kinds of new things, such as putting the genes from animals into a
plant. For example, to make a fruit like strawberries stay fresh longer,
scientists took a gene from a fish--a gene that helps the fish live in cold water
and put that into a strawberry. Will that strawberry be harmful to people? We
don't know. Bur it may be.
So it's clear that there are some important benefits to genetically modified
food but also some risks-risks that a lot of people aren't willing to take. So let's
stop here and discuss any questions you have at this point…
1. What is genetically modified food?
a. Fresh food b. Dangerous food c. Altered food
2. What genetically modified fruit did the speaker mention?
a. Strawberries b. Apples c. Bananas
3. What is a benefit of genetically modified food?
a. It needs fewer pesticides. b. It grows in less space. c. It dominates the environment.
4. What is a risk of genetically modified food?
a. It may stay fresh longer. b. It may be more expensive. c. It may be harmful to people.
5. What are three benefits of genetically modified food?
Genetically modified food needs fewer pesticides. Genetically modified food/plants grow better than normal. In addition, they stay fresh longer after they are harvested.
6. What are three risks of genetically modified food?
Genetically modified food/plants may dominate other plants in the environment. Also, they might hurt wild animals and insects. They might even hurt the people who eat them.
