【考托提分】小站独家深度解析官方原题Official32——听力Lecture1文本

Listen to part of a lecture in an Archeology class.

(Female professor) One of the important aspects of the field of archeology, uh, one of the things that excites me about the field is that seemingly insignificant things can suddenly change the way we think about a culture. We're always making new discoveries that have the potential to challenge widely held beliefs. Take something like the banana, for example. It turns out that this ordinary fruit may be forcing scientists to re-write major parts of African history. We know that bananas were introduced to Africa via Southeast Asia. And until recently, we thought we knew when mey were introduced: about two thousand years ago. But, discoveries in Uganda, that's in eastern Africa, are throwing that into question. Scientists studying soil samples there discovered evidence of bananas in sediment that was five thousand years old. Now, let me explain that it's not easy to find traces of ancient bananas. The fruit is soft and doesn't have any hard seeds that might survive over the ages. So, after five thousand years you might think there would be nothing left to study. Well, fortunately for archeologists, all plants contain what are called phvtoliths in their stems and leaves.Phytoliths are microscopic structures made of silica and they do not decay. When plants die and rot away, they leave these phytoliths behind. Because different plants produce differently shaped phytoliths, scientists can identify the type of plant from ancient remains. So, those scientists in Uganda dug down to sediments that were five thousand years old. And what do you think they found? Banana phytoliths! Obviously this meant that we had to rethink our previous notions about when bananas first arrived in Africa. But well, this discovery had other implications for history: as soon as bananas appear in the archeological record, we know we have contact between Africa and Southeast Asia. It would appear now that this contact occurred much earlier than previously thought. Although now here is where the uncertainty comes in,we don't really have any solid evidence of trade between the peoples of these two regions that long ago.

Presumably, if people were bringing bananas to Africa, they'd also be bringing other things, too, pottery, tools, all sorts of objects made for trade or daily use. But any such evidence is missing from the archeological record. Urn, the early appearance of bananas also suggests that agriculture began in this part of Africa earlier than scientists imagined. You see, bananas, at least the edible kind, can't grow without human intervention. They have to be cultivated, uh, people need to plant them and care for them. So, if bananas were present in Uganda five thousand years ago, we have to assume that someone planted them. But there are questions about this, too. We know that bananas can be a staple food that can support large populations as they did in Uganda in the more recent past. If bananas were grown thousands of years ago, why don't we see evidence of large populations thriving in the area earlier? So, we are left with this mystery. We have what appears to be strong biological evidence that bananas were being cultivated in Uganda as early as five thousand years ago. But we are missing other kinds of evidence that would conclusively prove that this is so. Clearly, more research needs to be done. Perhaps by some young scholars from this university? At least give it some thought.