Animal fossils usually provide very littleopportunity to study the actual animal tissues because in fossils the animals'living tissues have been largely replaced by minerals. Thus, scientists were veryexcited recently when it appeared that a 70-million-year-old fossil ofTyrannosaurus rex (T. rex), a dinosaur, might still contain remains of theactual tissues of the animal. The discovery was made when researchersdeliberately broke open the T. rex’s leg bone, thereby exposing its insides toreveal materials that seem to be remains of blood vessels, red blood cells, andcollagen matrix.
动物化石很难帮助人们研究动物的软组织，这是因为化石里面的动物活性组织大部分都被矿物质代替了。最近，发现一个7千万年前的霸王龙化石中可能存在真正的动物软组织。这令科学家们非常兴奋。科学家小心翼翼地打开了霸王龙腿骨的时候，发现里面存在着可能为血管、血红细胞和胶原蛋白基质的物质。
First, the breaking of the fossilized legbone revealed many small branching channels inside, which probably correspondto hollows in the bones where blood vessels were once located. The excitingfinding was the presence of a soft, flexible organic substance inside thechannels. This soft substance may very well represent the remains of the actualblood vessels of T. rex.
首先，打开腿骨化石之后，科学家发现了内部有一些管状分支，这些管状分支可能是骨内血管存在的地方。令人兴奋的是在这些管状分支中存在着柔软的有机物质。这些柔软的物质可能是霸王龙真正血管的遗留痕迹。
Second, microscopic examination of thevarious parts of the inner bone revealed the presence of spheres that could bethe remains of red blood cells. Tests showed that the spheres contained iron – a materialvital to the role of red blood cells in transporting oxygen to tissues.Moreover, the spheres had dark red centers (substances with iron tend to bereddish in color) and were also about the size of red blood cells.
第二，通过显微镜对骨内部多处进行详细检查之后发现了一些可能是血红细胞化石的球状体。检测发现这些球状体里面还有铁，而铁在血红细胞往组织内输送氧气的过程中扮演重要角色。而且，这些球状体中间呈红色，而含有铁元素的物质往往是红色的，同时这些球状体的大小也符合血红细胞。
Third, scientists performed a test on thedinosaur leg bone that showed that it contained collagen. Collagen is a fibrousprotein that is a main component of living bone tissue, in which it forms a so-calledcollagen matrix. Collagen (or its chemical derivatives) is exactly the kind ofbiochemical material that one would expect to find in association with bonetissue.
第三，科学家的测试发现这个恐龙腿骨化石中还有胶原蛋白。胶原蛋白是一种纤维化蛋白质，是生物骨组织的重要组成部分，以胶原蛋白基质的形式存在。胶原蛋白或者其衍生物是一种存在于骨骼软组织中的生化物质。
托福综合写作阅读部分需要提取的观点是：
- Main point: 科学家在研究霸王龙腿骨化石的时候，发现里面存在着可能为血管、血红细胞和胶原蛋白基质的物质。
- Sub point 1: 化石中有血管
- Sub point 2: 化石中有血红细胞
- Sub point 3: 化石中有胶原蛋白
托福综合写作听力材料：
As much as we would like to have theremains of actual dinosaur tissue, there are sound reasons for being skepticalof the identifications made in the reading.
尽管我们都希望这些化石是真正的恐龙组织，但是还是有一些很有说服力的理由让我们怀疑阅读部分的发现。
First, the soft, flexible substance insidethe bone channels isn’t necessarily the remains of blood vessels. It is muchmore likely to be something else. Like what? You might say. Well, long after anorganism is died, bacteria sometimes colonize hollows, empty areas in bones,like the channels that once held blood vessels. When bacteria lived insidebones, they often leave behind traces of organic material. What the researchersin the reading are identifying as blood vessels might just be traces of softand moist residue left by bacteria colonies.
首先，骨管内柔软而有延展性的物质不一定就是血管的化石。它更大的可能性是别的东西。那是什么呢?你们可能会问。恩，在有机体死亡很久之后，细菌可能会聚集在骨骼里的空洞的地方，比如那些曾经是血管存在的地方。当细菌在骨骼内部繁殖后，细菌常常会留下有机物质的痕迹。在阅读部分，研究人员鉴定为血管的物质很可能就是细菌繁殖后留下的湿软残渣的痕迹。
All right. What about the iron-filledspheres? Well, the problem is that scientists found identical reddish spheresin fossils of other animals found in the same place. That includes fossils of primitiveanimals that did not have any red blood cells when they were alive. Clearly, ifthese spheres appear in organisms that did not have any red blood cells, thenthe spheres cannot be the remains of red blood cells. The spheres probably havea very different origin. They are probably just pieces of reddish mineral.
恩，那么那些含铁的球状体呢?问题在于科学家们在同一个地方发现了其他还有动物的还有红色球状体的化石。这些化石中有的是属于一些活着的时候没有任何血红细胞的低等动物。显然，如果这些球状体出现在那些没有任何血红细胞的动物化石组织里的话，那么这些球状物就不可能是血红细胞的残留物。这些球状体可能有完全不同的来源。它们可能只是一些红色矿物质颗粒。
Third, the collagen. The problem is that wehave never found collagen in animal remains that are older than one hundredthousand years. Collagen probably cannot last longer than that. Finding collagenfrom an animal that lived seventy million years ago would really contradict ourideas about how long collagen can last. It is just too improbable. The mostlikely explanation for the presence of collagen is that it doesn’t come fromthe T.rex, but from another much more recent source. For example, human skincontains collagen, so the collagen may have come from the skin of theresearchers who are handling the bone.
第三，胶原蛋白。问题在于我们从来没有在超过十万年的动物化石中发现胶原蛋白。胶原蛋白可能不能存在超过一万年。在生活在七千万年前的动物化石里发现胶原蛋白是同我们对于胶原蛋白存在时间的认识相矛盾的。这种可能性太低了。最为合理的解释是这些胶原蛋白不是来自于霸王龙，而是来自于其他的，更近的来源。比如，人类的皮肤中还有胶原蛋白，所以这些胶原蛋白可能来自于那些处理化石的研究人员的皮肤。
托福综合写作听力笔记：
- Main point: 阅读部分的发现是值得怀疑的
- Sub point 1: 细菌会侵袭死亡有机体，研究人员鉴定为血管的部分可能是细菌的遗迹
- Sub point 2: 含铁红色球状物在其他没有血红细胞的动物化石中也有发现，可能是矿物颗粒
- Sub point 3: 胶原蛋白不可能存在那么长时间，很可能来自于研究人员
托福综合写作范文(仅供参考)：
The reading passage points out threeevidences that indicate the existence of actually tissue in dinosaur fossil.However, the professor doubts the accuracy of these evidences. In fact, heoffers some alternative explanations for the substances found in the fossil.
First and foremost, he challenges theexistence of blood vessels. Instead, he points out that bacteria may occupy thehollows inside the bones. Therefore, it is highly possible that the soft substancein the branching channels of the bone is the moist residue of bacteria, ratherthan blood vessels of the dinosaur.
Moreover, the professor casts doubt aboutthe red substance in sphere, which according to the reading passage is theremain of red blood cells. In fact, the professor claims that this red substancewas also found in some other animals, which lived in the same place but had nored blood vessels at all. The professor argues that the sphere can be pieces ofred minerals.
Additionally, the professor doubts theexistence of collagen in the fossil. On the contrary to the reading passage, hepoints out that the earliest collagen that has ever found is in fossils 100000 ago.It is unlikely for collagen to last for more than 70 million years. As aresult, the professor suggests that the collagen may come from recent sources,such as the skin of researchers who handed the fossil.