为了帮助大家高效备考托福，为大家带来托福TPO4综合写作阅读原文+听力原文+满分范文，希望对大家备考有所帮助。什么是蓝筹股
大气压产生的原因 托福TPO4综合写作阅读原文文本：
愚者千虑
Endotherms are animals such as modern birds and mammals that keep their body temperatures constant. For instance, humans are endotherms and maintain an internal temperature of 37°C, no matter whether the environment is warm or cold. Becau dinosaurs were reptiles, and modern reptiles are not endotherms, it was long assumed that dinosaurs were not endotherms. However, dinosaurs differ in many ways from modem reptiles, and there is now considerable evidence that dinosaurs were, in fact, endotherms.
Polar dinosaurs
One reason for believing that dinosaurs were endotherms is that dinosaur fossils have been discovered in polar regions. Only animals that can maintain a temperature well above that of the surrounding environment could be active in such cold climates.
Leg position and movement
三大推理文学宗师 There is a connection between endothermy and the position and movement of the legs. The physiology of endothermy allows sustained physical activity, such as running. But running is efficient only if an animal's legs are positioned underneath its body, not at the body's side, as they are for crocodiles and many lizards. The legs of all modern endotherms are underneath the body, and so were the legs of dinosaurs. This strongly suggests that dinosaurs were endotherms.
Haversian canals
There is also a connection between endothermy and bone structure. The bones of endotherms usually include structures called Haversian canals. The canals hou nerves and blood vesls that allow the living animal to grow quickly, and rapid body growth is in fact a characteristic of endothermy. The prence of Haversian canals in bone is a strong indicator that the animal is an endotherm, and fossilized bones of dinosaurs are usually den with Haversian canals.
托福TPO4综合写作听力原文文本：
Many scientists have problems with the arguments you read in the passage. They don't think tho arguments prove that dinosaurs were endotherms.
Take the polar dinosaur argument. When dinosaurs lived, even the polar regions, where dinosaur fossils have been found, were much warmer than today, warm enough
during part of the year for animals that were not endotherms to live. And during the months when the polar regions were cold, the so-called polar dinosaurs could have migrated to warmer areas or hibernated like many modern reptiles do. So the prence of dinosaur fossils in polar regions doesn't prove the dinosaurs were endotherms.
海鲶鱼怎么做好吃 Well, what about the fact that dinosaurs have their legs placed under their bodies, not out to the side like crocodiles. That doesn't necessarily mean dinosaurs were high-energy endotherms built for running. There is another explanation for having legs under the body. This body structure supports more weight, so with the legs under their bodies, dinosaurs can grow to a very large size. Being large had advantages for dinosaurs, so we don't need the idea of endothermy and running to explain why dinosaurs evolved to have their legs under their bodies.
什么首什么胸
Ok, so how about bone structure? Many dinosaur bones do have Haversian canals, that's true. The dinosaur bones also have growth rings. Growth rings are thickening of the bone that indicates periods of time when the dinosaurs weren't rapidly growing. The growth rings are evidence that di
nosaurs stopped growing or grew more slowly during cooler periods. This pattern of periodic growth, you know, rapid growth followed by no growth or slow growth, and then rapid growth again, is characteristic of animals that are not endotherms. Animals that maintain a constant body temperature year-round as true endotherms do grow rapidly even when the environment becomes cool.电蚊香液
托福TPO4综合写作满分范文：
The professor actually contradicts the statements made in the passage. She is of the view that dinosaurs are not they were not able to keep their body temperature at a constant rate.
The professor contradicts the issue of dinosaurs being endothers bad on the availability of fossils being available in the polar regions, she say that the polar regions in tho days were not as cold as they are today i.e at least warm enough for dinosaurs to live. Durin harsh winters she says that there is a possibility of the dinosaurs actually migrating to warmer regions.
The issue of leg position and movement being ud as a reason to clasify the dinosaurs as endotherms does not plea the professor either. She says that dinosaurs had legs under their bodie
大学生目标规划s to support their huge bodies i.e the legs under the body of the dinosaur were actually to support the huge weight of the dinosaur and not to provide it with a body structure like endotherms(which is actually suited for running).
The professor acknowledges the prence of haversian canals but also points out that that the fossils show the prence of growth rings. The rings occur due to the thickening of the bone. The thickening indicates that the dinosaurs were’nt
