托福考试听力加试题：大王花（题目及答案）

quickly about another plant, a plant that's also from the forests of Southeast Asia, called Mitrastema.

　　Now, Mitrastema is also a parasite, which led some to believe that Rafflesia was related to Mitrastema—that they belong to the same order. Mitrastema as I said is a parasite, but its flowers are much smaller, and don't smell bad, so you can see why there was debate about whether they were related. But as it turns out, Mitrastema is actually related to blueberries. So, even plants that share an unusual characteristic with Rafflesia are not related to it. And, um...no plant shares all three of its unusual characteristics, and that made classifying Rafflesia very, very difficult."

　　Now, you're probably thinking, why don't they just analyze the DNA of the plant Well, as I said, Rafflesia is a parasite. It lacks the leaves; the green tissue that most plants need for photosynthesis. It's unable to...um...to capture the sunlight most other plants use to make food. So, it's lacking...it...it...it doesn't have the DNA—the genes—for photosynthesis, which is what we usually use to classify plant species. But some researchers in Michigan persisted, and analyzed about 90 species of seed plants and compared them to Rafflesia, and we finally had an answer. Rafflesia was part of the Malpighiales order.

　　Now, other species in the Malpighiales order include violets ... um ... poinsettias ... uh ... passion – flowers ...what else Willows. So it was pretty unexpected because flowers like violets are a lot smaller than Rafflesia, right And they don't smell bad—they don't smell like rotting meat...and they're not parasitic. It took almost 200 years to classify Rafflesia, to identify its relatives, and I don't think anyone would have ever guessed that it's in the order Malpighiales. I mean...you know-it'd be nice to be able to classify species based on their obvious characteristics, but, it didn't work that way with Rafflesia. And unfortunately for Rafflesia, and for the field of botany, it seems that Rafflesia may be dying out. It's certainly endangered because of deforestation in its habitat. And to make matters worse, Rafflesia doesn't reproduce very well. First of all, only 10-20% of buds turn into full-fledged flowers, and it can take them a year to grow. There are also male flowers and female flowers, and one of each has to be in the same area—the same vicinity—at the same time, to produce seeds, and the flies that are attracted to the flower's strong smell have to carry pollen from one flower to the other, so how often do you think these events occur all together Even people who study the plant for years may never witness it.

　　题目:

　　问题一：主旨题

　　What is the lecture mainly about

　　正确答案：(C) 植物的分类困难。

　　问题二：细节题

　　How does a strong odor help Rafflesia

　　正确答案：(D) 吸引flies过来，帮助它授粉。

　　问题三：细节题

　　Why does the professor consider the actual classification of Rafflesia unexpected

　　正确答案：(A) 这些植物的特征和大王花不同。

　　问题四：细节题

　　What does the professor imply about the reproduction of Rafflesia

　　正确答案：(B) 很少见。

　　问题五：重听题

　　Listen to part of the lecture again and then answer the question.

　　It actually grows inside its host, which is a type of grapevine. I mean... it grows inside its host until it blooms-it doesn't bloom inside the host.

　　What does the professor say this:

　　"...I mean... it grows inside its host until it blooms-it doesn't bloom inside the host...."

　　正确答案：(B) 解释清楚，避免学生被误导。

　　问题六：重听题

　　Listen to part of the lecture again and then answer the question.

　　But as it turns out, Mitrastema is actually related to blueberries. So, even plants that share an unusual characteristic with Rafflesia are not related to it. And, um... no plant shares all three of its unusual characteristics, and that made classifying Rafflesia very, very difficult.

　　What does the professor imply when she says this:

　　"But as it turns out, Mitrastema But as it turns out, Mitrastema is actually related to blueberries."

　　正确答案：(C) Rafflesia和Mitrastema隶属不同目。