TPO9

The lecturer points out several problems with the use of hydrogen-based fuel-cell engines in support of her claim that substituting them for internal-combustion engines is technologically unfeasible, environmentally unfriendly, and economically unviable.

First, the lecturer states that it is impractical to replace internal-

combustion engines with fuel-cell engines because using the latter requires hydrogen in a pure liquid form, which is technologically challenging to both obtain and store. However, the reading argues that because hydrogen can be extracted from many resources including water, fuel cell engines powered by this infinite source of energy are an extremely attractive alternative.

Second, the lecturer refutes the claim in the reading that hydrogen cells are environmentally friendly. She argues that although engines that use hydrogen cells produce less pollution, the manufacturing of hydrogen cells generates large amounts of harmful by-products due to the burning of fossil fuels in the purification process.

Third, although the reading suggests that hydrogen-based engines are more fuel-efficient and thus economically competitive than internal-

combustion engines, the professor argues that such an advantage is

undermined by the fact that fuel-cell engines are extremely expensive to manufacture because they require the addition of platinum, a very rare and expensive material.

TPO10

The lecturer and the reading passage suggest two competing theories, the predation theory vs. the pollution theory, to explain why the sea otter population is in rapid decline.

The professor reasons that the absence of dead sea otters washed up the coast suggests that their decline is not caused by sea pollution but rather by sea predators who consume their bodies after Killing them. In contrast, the reading passage attributes the death of sea otters to pollution, citing evidence of

increased sources of ocean contaminants which lead to greater vulnerability to infections.

Furthermore, the lecturer argues that orcas are likely factors in the

disappearance of sea otters, because the scarcity of whales, their usual prey, has left them with no other choice but to start hunting smaller mammals like the otters for food. The reading passage, on the other hand, Rules out this theory based on the orca’s preying habit, and instead approves of the pollution theory as the only explanation for the decline op both large and small sea mammals across the entire ecosystem.

Finally, according to the lecturer, the uneven pattern of sea otter decline corresponds to the distribution of the orcas. She argues that the pact that their population has declined most rapidly where orcas are most prevalent further validates the predation theory. However, the reading passage argues that changeable environmental factors, which lead to different concentrations of pollutants, better explains the varying pattern of sea otter decline.

TPO3

The lecture revises the idea presented in the text, that Rembrandt was not the artist who painted the famous painting “Portrait of an Elderly Woman in a White Bonnet”.

The inconsistency between the white cap, which identifies the woman as a servant, and the expensive fur collar she wears dissolves as the Professor

explains that the fur collar was apparently painted over the original painting to increase its worth by displaying an aristocratic woman.

In addition, the assumption that light and shadow in the painting do not fit together is refuted by the fact that in the original painting, the woman wears a light cloth that illuminated her face. Thus the presentation of light and shadow was indeed very realistic and accurate, as it is characteristic of Rembrandt’s paintings.

Finally, the mystery of the panel consisting of patches glued together is also solved in the lecture. Actually, the wood panel was later enlarged to make it

more grand and valuable, but the original painting was painted on a single panel,

as Rembrandt would have done it. Furthermore, the wood is of the same tree used in other Rembrandt paintings, like the “Self-Portrait with a Hat”.

All this information points to Rembrandt as the painter of the controversial painting.

TPO4

The professor actually contradicts the statements made in the passage. She is of the view that dinosaurs are not endotherms i.e. they were not able to keep their body temperature at a constant rate.

The professor contradicts the issue of dinosaurs being endotherms based on the availability of fossils being available in the polar regions, she say that the polar regions in those days were not as cold as they are today i.e at least warm enough for dinosaurs to live. During 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 used as a reason to classify the dinosaurs as endotherms does not please the professor either.She says that dinosaurs had legs under their bodies 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 presence of haversian canals but also points out that that the fossils show the presence of growth rings. These rings occur due to the thickening of the bone. The thickening indicates that the dinosaurs weren’t actually growing continuously but were experiencing periods of rapid growth and periods of no growth in succession. This pattern. She says is characteristic of non endothermic animals.

Thus it can be inferred that the professor challenges the passage by giving reasons as to why she thinks that the dinosaur is not an endotherm.

 

第二篇：托福试题：TPO 3【精选】独立写作满分作文

托福试题:TPO 3独立写作满分作文

智课网出品

TPO,全称TOEFL Practice Online,是ETS有偿提供给考生的托福备考材料,是ETS之前考过的托福试题,对于托福考生考前模拟和复习具有很大的价值,智课网为大家带来托福TPO 3独立写作试题并附托福作文范文及托福满分作文答题要点，考生们要认真备考。

托福TPO3 独立写作试题： It is more important to keep your old friends than it is to make new friends.

托福满分作文-范文赏析：

In our lifetime, we move from one school to another, then one job to the next, and, along the way, we pursue various leisure activities which all put us into contact with different people. Some of these people naturally become friends and some friendships stick while others do not.

For humans, as social animals, friends provide an alternative to family ties as a

shoulder to lean on, someone to turn to for help and advice, or just someone to talk to and share time with. They become an essential part of one’s life and bonds can quickly form. Yet, as we switch careers or hobbies, these bonds may seem to become less immediately useful in our new surroundings due to distance or knowledge. Good friendships naturally tend to outlast these moves as closeness and trust evolves beyond the passing acquaintance stage. Trying to keep friendships alive that are less firmly grounded can be time-consuming and unproductive, since the likelihood of being ‘useful’ may outweigh their potential benefit. Even though, it may seem mercenary to describe friendships in such a way, thus it is no doubt how we instinctively act. Gathering lots of acquaintances implies lots of time and effort for shallow relationships with little meaning and little potential pay-off. Only deep relationships can supply the kind of support we need that we can otherwise only find from a family.

Some people are adept at networking; they naturally gather many friends

throughout each stage of their lives; while others are less socially inclined. For those more socially-skilled, they no doubt maintain a mixture of connections with people, some deeper than others. They may manage their associations with others to the best effect for profit in careers or politics, or they do so just to be around people of whom they enjoy the company. For most people, there comes a time when old connections fade as new ones appear due to new circumstances and new needs. Devotion to old friends is lost due to time pressure whilst newly-made friendships are cultivated due to need. These new friendships need a lot of effort and time to build up the necessary trust, comfort levels and shared memories felt with old associates. It takes time and various situations to gauge if someone is a true or a fair-weather friend. No doubt we all naturally assess our new contacts’ personalities, common interests, and thereby invest a lot into this process.

In conclusion, beneficial though keeping old friends is, the virtues of making new ones cannot be easily neglected. New opportunities require new relationships

whereas time considerations demand that some old friendships need to be sacrificed.

托福作文满分要素剖析:

一、 语言表达

本文多用长句和并列结构。读来略显晦涩，但是细读之后值得回味。是作者高超语言功力的体现。而且作者的用词非常准确讲究，非一般考生所能驾驭，立刻总其他作文中脱颖而出。

1. In our lifetime, we move from one school to another, then one job to the next,

and, along the way, we pursue various leisure activities which all put us into contact with different people.本文用了两种指代。Another指代School，next指代the next job，这是很常用的一种英文表达方式。而且作者使用了两个插入语，调整了句子的停顿和节奏。

2. Some people are adept at networking; they naturally gather many friends

throughout each stage of their lives; while others are less socially inclined.本句是典型的并列句式。分号表示句子并列，相当于and，使句子间的联系更紧密了。而且本句的用词也十分讲究。Be adept at表示熟练，是skilled的替换词。Incline表示倾向于。是分词作定语的用法。

3. It takes time and various situations to gauge if someone is a true or a

fair-weather friend.本句的用词值得借鉴。Gauge表示仔细研究。Fair weather表示忠实的，都可以在今后使用。

二、 逻辑结构

本文不是传统的总分总结构，而是采用了分总的结构。层层递进。首先点明主题，并对主题词友情进行分析。之后从老朋友和新朋友两方面分别进行分析。并从不同人的角度分别进行了深入分析。最后提出了自己的观点，即新老友情都很重要。

智课网温馨提醒：考生们拿到托福作文试题，审题后，先决定总体思路，然后列出两三个具体的分论点，每个论点找出一些例子来说明。这里要注意例子的选择，尽可能生活化、生动化、形象化，不要太死板，托福写作模板和范文仅供大家学习和借鉴，不要生硬的背诵。祝各位托福考生能够取得满意的托福满分作文。