TPO11 Lecture 3 Environmentalscience.doc

TPO11 Lecture 3 Environmental science

Narrator
Listen to part of a lecture in an environmental science class.

Professor
When land gets develop for human use, the landscape changes.(主旨句？） We don’t see
as many types of vegetation, trees, grasses and so forth. This in turn leads to
other losses: the loss of animal that once lived there. Err…but these are the
obvious changes, but (转折）there are also less obvious changes like the climate.
One interesting case of this…of…of changes in the local land use causing
changes in climate, specifically the temperature is in Florida. Now what comes
to mind when you think of the state of Florida?

Student A
Sunshine, beaches.

Student B
Warm weather, oranges…

Professor
Yes, exactly. Florida has long had a great citric industry; large growth of
oranges, lemons and the like. Florida’s winter is very mild; the temperature
doesn’t often get below freezing. But there are some areas in Florida that do
freeze. So（因果） in the early 1900s, farmers moved even further south in Florida, to
areas that were even less likely to freeze. Obviously, freezing temperatures
are danger to the crops. A bad barrier of cold weather, a long spell of frosts
could ruin a farm and the entire crop, anyway, before these citric growers
moved south, much of the land in south Florida, was what we called wetlands（专有名词）.
Wetlands are areas of marshy, swampy land, areas where water covers the
soil, or is present either at or near the surface of the soil for large part of the
year. Wetlands have their own unique ecosystem, with plants and animals with
special an interesting adaptation. Very exciting, but it’s not what we are talking
about today. Emm…where was I?（现在原则）

Student A
Farmers moved south?

Professor
Oh, yes. Farmers moved south. But（转折） the land was not suitable for farming. You
can’t grow orange in wetland, so(因果） farmers had to transform the wetlands into
lands suitable for farming. To do that, you have to drain the water from the land,
move the water elsewhere, and divert to the water sources such as rivers.
Hundreds of miles of drainage canals were built in the wetlands. Now（转化话题） these
areas, the new areas the farmers moved to, used to be warm and unlikely to
freeze, however, recently（对比） the area has become susceptible to freezes. And we
are trying to understand why.

Student B
Is it some global temperature change or weather pattern like El Ni?o or
something?（转化话题）

Professor
Well, there are two theories（并列）. One idea is as you suggested that major weather
patterns, something like El Ni（专有词汇）?o, are responsible. But the other idea and this is
the one that I personally subscribe （赞成，态度）to, is of the changes in the temperature
pattern had been brought about by the loss of wetlands.

Student A
Well, how would the loss of wetlands make a difference?（转化话题）

Professor
Well, think about what we’ve been studying so far. We discussed the impact of
landscapes on temperature, right? What affects（因果） does the body of water have
on an area?（转化话题）

Student A
Oh, yeah. Bodies of water tend to absorb the heat during the day, and then
they release the heat at night.

Professor
Yes, exactly. What you just said is what I want you all to understand. Bodies of
water release heat and moisture back into the environment（重复强调）. So（因果） places near
large bodies of water are generally milder, err...slightly warmer than those
without water. And what I, another think is that the loss of the wetlands has
created the situation where the local temperatures in the area are not slightly
different, slightly colder than they were 100 years ago, before the wetland were
drained.

Student B
Emm…do we know what the temperature was like back then?（转化话题）语气

Professor
Well, we were able to estimate this. We have data about South Florida’s
current landscape, emm…the plant cover. And we were able to reconstruct
data about the landscape prior to 1900. Then we enter those data, information
about what the landscape look like before and after the wetlands were drained.
We enter the data into a computer weather model. This model can predict
temperatures. And when all the data were entered, an overall cooling trend
was predicted by the model.（过程）

Student B
How much colder does it get now?

Professor
Well, actually the model shows a drop of only a few degrees Celsius. But this is
enough to cause dramatic damage to crops. If temperatures over night are
already very close to the freezing point, then this drop of just a few degrees
can take the temperature below freezing. And freezing causes frosts, which kill
crops. These damaging frosts wouldn’t happen if the wetlands were still in
existence, just as the tiny temperature difference can have major
consequences.

1. what is the lecture mainly about?（主旨题）
l The effect of the decrease in temperatures on wetlands（顺序不对）
l The use of computer models to analyze temperature patterns（细节）
l The theory that land development affected the climate of South Florida
l The importance of the citrus industry to the south Florida economy（无中生有）
2. why does the professor mention the building of canals in the wetlands?（举例目的题）
l To describe what the wetlands used to look like（无中生有）
l To emphasize that farmers need to transport their crops to other areas（张冠李戴）
l To explain how the wetlands were transformed into farmland
l To explain why people want to build farms there（顺序不对）
3. what does the professor imply about major weather patterns such as EI NINO?（推断题，态度考点）
l She does not believe they are the main cause of the changes in Florida's climate
l She is certain that they have caused a worldwide decrease in the number of frosts
l She believes they contributed to the increase of citrus production in Florida
l She does not fully understand what causes them
4. what point about bodies of water does the professor emphasize to the students?（强调考点）
l Bodies of water in Florida are slightly warmer now than they were 100 years ago.
l Bodies of water in south Florida are increasing in size
l Bodies of water release heat back into the environment
l Bodies of water are a source of moisture for crops
5. What data from 100 years ago and today were entered into the computer model that the professor discusses?（？？？）过程
l The average temperatures in south Florida
l The market prices of citrus fruit grown in south Florida
l The numbers of animal species in south Florida wetlands
l The landscape characteristics of south Florida
6. Why does the student say this()（重听题)
l To remind the professor of her previous point
l To check if he understood the professor's point
l To express surprise at what the professor said
l To answer the professor's question about the farmers