首页>>TPO>>TPO 24
托福写作真题练习

独立写作重点机经

综合写作

TPO  TPO 24 综合写作

所属分类: 考古
目前共有725位会员练习过本题.
Reading Part:
Animal fossils usually provide very little opportunity to study the actual animal tissues, because in fossils the animals' living tissues have been largely replaced by minerals. Thus, scientists were very excited recently when it appeared that a 70-million-year-old fossil of Tyrannosaurus rex (T. rex), a dinosaur, might still contain remains of the actual tissues of the animal. The discovery was made when researchers deliberately broke open the T. rex’s leg bone, thereby exposing its insides to reveal materials that seem to be remains of blood vessels, red blood cells, and collagen matrix.

First, the breaking of the fossilized leg bone revealed many small branching channels inside, which probably correspond to hollows in the bones where blood vessels were once located. The exciting finding was the presence of a soft, flexible organic substance inside the channels. This soft substance may very well represent the remains of the actual blood vessels of T. rex.

Second, microscopic examination of the various parts of the inner bone revealed the presence of spheres that could be the remains of red blood cells. Tests showed that the spheres contained iron-a material vital to the role of red blood cells in transporting oxygen to tissues. Moreover, the spheres had dark red centers (substances with iron tend to be reddish in color) and were also about the size of red blood cells.

Third, scientists performed a test on the dinosaur leg bone that showed that it contained collagen. Collagen is a fibrous protein that is a main component of living bone tissue, in which it forms a so-called collagen matrix. Collagen (or its chemical derivatives) is exactly the kind of biochemical material that one would expect to find in association with bone tissue.

中文翻译:
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。
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。
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。
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。
Listening Part:
Question:
Summarize the points made in the lecture, being sure to explain how they cast doubt on specific points made in the reading passage.
用微信扫一扫
分享本题目到朋友圈
与“考古”相关的题目
暂无