托福TPO50[综合写作&独立写作]写作试题+范文汇总

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托福TPO50综合写作范文

Scientists are considering the possibility of sending humans to Mars in the coming decades. Although there have been successful manned missions to the Moon in the 1960s and 1970s, Mars is 150 times further away from Earth than the Moon is. Thus the project of sending humans to Mars would require solving an array of problems the Moon missions did not have to face.

One problem is that a round-trip to Mars and back is likely to take at least two years. The trip to the Moon lasted only a few days, and it was easy to bring enough supplies of food, water, and oxygen; but the cargo capacity of space vehicles is too limited to put on board the food, water, and oxygen required by a crew for a period of two years. Without those essentials, though, a Mars mission is impossible.

A second problem is that astronauts on the Mars mission would be in the zero-gravity environment of space for many months at a time. Spending a long time in the zero-gravity environment has negative effects on the human body, such as decreased muscle mass and lower bone density. Over the course of a two-year mission, the effects would be so severe, they would make it impossible for humans to make the trip without experiencing grave medical problems.

Finally, astronauts on a mission to Mars would be exposed to dangerous levels of space radiation, much of which comes in the form of charged particles emitted by the Sun. Earth’s magnetic field, which normally protects us from dangerous solar radiation, would not be able to protect a spaceship traveling in interplanetary space. Constructing a shield that would protect the whole spaceship from space radiation is at present impossible because it would add too much weight to the ship.

托福TPO50独立写作范文

University courses lay a very solid academic foundation for the future development of college students. Facing the great selections of these courses, some say that history classes should be made compulsory for college students, for the reason that they could be more familiar with the advancement and evolution of human society. I disagree. I believe, despite minor merits, asking students of all majors to attend history classes would be problematic.

Initially, history courses would exert more academic pressure on students. College students have already had to study many theories and professional subjects related to their majors and their schedule is very tight. For example, a medical student is not only obliged to finish his professional papers for credit, but he also needs to find the opportunity to get clinical experience. Likewise, a student majoring in Marketing is required to read piles of books and analyze numerous business cases. Besides, working part-time in local companies to put theory into practice is what occupies most of their free time. Their load, therefore, is so heavy that they could not afford to take any irrelevant courses, such as history. In this case, universities should not add this course, because students would worry whether they are able to finish their assignment on time and how likely they would pass final examinations.

In addition, a required history course would lead to unnecessary financial costs for parents and students. To guarantee the quality of lecturing, colleges have to hire talented and senior history professors and experts, such as those from the best-known universities or history research institutes. This would increase the cost of schooling. Normally, a lecture given by a famous history professor costs over a thousand dollars, and these costs would be reflected in the tuition fee, which would increase students’ financial pressure. The case of my cousin Jeremy, a first-year physics student in the University of Hong Kong, illustrates this point. At the end of last semester, he was told to pay extra two thousand dollars for this year’s school fees because of the addition of a compulsory forty-hour course on World History on their syllabus. As this was hardly affordable for his family, they needed to take out a loan from a bank in the end.

Admittedly, taking history courses does have its merits. On the one hand, students could learn to prevent repeating the mistakes of the past. For instance, they would learn about the cause of the world wars and other bloody battles that claimed the lives of millions. On the other hand, students could also gain a better understanding of current issues by studying historical events. For example, by studying the American Revolution a student could be enlightened on the current world democracy. However, this knowledge could be acquired by other methods other than required courses; history seminars, TV documentaries and comparable books are all available options for students to learn about history.