托福聽(tīng)力lecture并列型分析

之前我們介紹了lecture的并列型結(jié)構(gòu)，一般是圍繞某一個(gè)主題并列平行展開(kāi)去講解。這類結(jié)構(gòu)沒(méi)有之前我們見(jiàn)到的直線型結(jié)構(gòu)那么好區(qū)分，因?yàn)樗麤](méi)有明顯的表示時(shí)間地點(diǎn)人物的信號(hào)詞，但是這種結(jié)構(gòu)類型是我們TPO和考試中出現(xiàn)的比較多的結(jié)構(gòu)類型。我們這次分析一篇按并列結(jié)構(gòu)分層的文章。

今天我們以TPO30-L2為例，給大家講解一下。

As we’ve discussed, birds are apparently descendants of dinosaurs and shared many commonalities with some dinosaur species, like…um…feathers and maybe even flight and of course egg laid. OK.

So, many paleontologists, myself included, have wondered about other similarities between dinosaurs and birds. Since adult dinosaur fossils have sometimes been discovered near or on top of nests, we’ve been looking at the dinosaur parenting behavior. 首先我們先引出一個(gè)常見(jiàn)的觀點(diǎn)

Student

Parenting behavior, well, that sounds so gentle and caring. But dinosaurs were ferocious reptiles and reptiles don’t take care of their young, do they?一般我們認(rèn)為因?yàn)榭铸埵莾疵偷呐佬袆?dòng)物，所以是沒(méi)有養(yǎng)育行為的

Professor

Well, some reptiles incubate their eggs, crocodiles do. And as for popular attitudes towards dinosaurs…well, take the Oviraptor for instance.

In the 1920s, a paleontologist discovered the fossil remains of a small dinosaur near a nest containing eggs. He assumed the dinosaur was stealing the eggs, so he named it Oviraptor that means egg thief in Latin, which fueled the generally negative public image of such dinosaurs. 但是隨后就提出了相反的證據(jù)，Overaptor就是跟我們所想相反的一種動(dòng)物，它其實(shí)是在照顧恐龍蛋。

But by the 1990s, other experts had convincingly made the case that instead of robbing the nest; the Oviraptor was probably taking care of the eggs. You see, dinosaurs’ closest living relatives – birds and crocodiles – display nesting behavior. And dinosaur fossils have been found in postures that we now believe to indicate brooding behavior, that is, sitting on the eggs until they hatch.

So we are curious about the type of care dinosaurs gave to their young. And we’d like to figure out which dinosaur parent, the male or the female gave the care. 進(jìn)一步開(kāi)始研究，既然他們會(huì)照顧后代，那么到底是雄性還是雌性呢?

Student

Shouldn’t the behavior of crocodiles and birds give us some clues then?

Professor

Well, with crocodiles, it is the female who guards the nest, and with birds, it depends on the species, it can be the male or the female that takes care the eggs, or both. In over 90 percent of all bird species, both parents take care of the eggs and the young birds. 首先按常理來(lái)說(shuō)基本是雌性照顧幼崽的，或者是同時(shí)照顧。

Student

But sometimes it’s just the male?

Professor

Well, exclusive care by the male parent is much less common, but it does occur. Now, for animals other than birds, the care of young by both parents is pretty unusual in the animal kingdom. Males contribute to parental care in fewer than five percent of all mammalian species. It’s even less frequent among reptiles. And exclusive care by the male is very rare. So researchers have wondered about the evolution of male parenting behavior in birds for quite some time. And now there’s research showing that for some of the birds’ dinosaur relatives, it’s likely that the male parent was also in charge of taking care of the eggs. 但是之后又提出了不同的觀點(diǎn)，其實(shí)有時(shí)雄性也會(huì)參與到照顧幼崽的行為中

Student

How did they figure that out?

Professor

Well, first they looked at clutch volume, that’s the number of eggs in the nest of crocodiles, birds and three types of dinosaurs, including Oviraptors that are thought to be closely related to the dinosaur ancestors of birds.

So when researchers examined fossilized remains of nests, they found that the dinosaurs had larger clutch volumes, more eggs in the nests that is, than most of the crocodiles and birds that were studied. But, and this is important , their clutch volumes matched those of birds that have only male parental care. You see, bird species in which only the males take care of the nest tend to have the largest clutches of eggs. 后面提出了有力的證據(jù)clutch volume，來(lái)證明了之前的觀點(diǎn)。

Student

So what’s the connection between bird and dinosaur behavior?

Professor

Well, researchers now believe, because of this study, that the male parenting behavior of these birds might have its origins in the behavior of dinosaurs.

Student

Based only on evidence of clutch volume size, the number of eggs?

Professor

No, there’s more. They also examined the fossilized bones of those three types of dinosaurs that were found on or near nests to determine their sex. You see, adult female birds during egg production produce a layer of spongy bone tissue inside certain long bones. And so did female dinosaurs of the kinds that were investigated. This spongy tissue serves as a source of calcium for eggshell formation. But when the dinosaur fossils were examined, there were no spongy bone deposits. 最后又提出了另一個(gè)有利的證據(jù)spongy bone tissue來(lái)支持我們的觀點(diǎn)。

Student

Meaning that those dinosaurs on the nests were probably adult males who wouldn’t have needed calcium for making eggshells.

Professor

Exactly. And then there’s this: birds like the kiwi, the ostrich and the emu; they share certain physical characteristics with these dinosaurs. And interestingly, they also show a consistent pattern of nest care by the male.

所以整篇文章為了證明雄性會(huì)照顧幼崽，一步步的提出證據(jù)進(jìn)行論證，最終證實(shí)觀點(diǎn)。

當(dāng)然，在課程當(dāng)中，老師會(huì)給大家針對(duì)這種并列型結(jié)構(gòu)做充分的講解，如果有同學(xué)自己復(fù)習(xí)效果不是很好，可以通過(guò)的方式，找專業(yè)的老師來(lái)對(duì)大家的這部分進(jìn)行訓(xùn)練和提升。在這里小編祝大家在當(dāng)中取得優(yōu)異的成績(jī)。如果同學(xué)們對(duì)我們的感興趣，或是托福復(fù)習(xí)過(guò)程中遇到了問(wèn)題，都可以

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