1.专业方向；
2.选择理由；
3.如何准备。
注意：
1.词数100左右；
2.题目已为你写好。
题目:My Future Major
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2 . On paper, hydrogen（H2）looks like a dream fuel. Coal, oil, and natural gas produce carbon dioxide, which warms the earth when burned, Hydrogen produces pure water. Hydrogen packs more energy into less space than a battery（but certainly less than petrol）. Also, empty tanks（燃料箱）can be refilled with hydrogen much faster than refilling empty batteries with electricity.
While in practice, things are trickier. Storing a meaningful amount of hydrogen gas requires pressing it several hundred-fold. Changing it into the liquid form is another option, but it should be cooled to-253C. Both processes require a heavy and strong tank. While a 700 bar tank is acceptable for a city bus or a truck, adapting it for use in small vehicles is very difficult because the pressure during refilling would be too great.
The solution? Powerpaste.
A German team of researchers, led by Marcus Vogt, have come up with an interesting "powerpaste", which can store hydrogen energy at atmospheric pressure, ready for release when needed. It is so named because it comes in tubes and looks like toothpaste（牙膏）, not in its traditional form of gas.
The main ingredient（原料）of the paste is magnesium hydride, a substance that reacts with water to form hydrogen. The escaped hydrogen can then be directed into a fuel cell, where it reacts with oxygen from the air to produce electric power.
Refueling is very simple, as instead of going to a filling station, drivers and riders can simply replace an empty tube with a new one and refill the water tank.
Given that powerpaste only begins to break down at temperatures of around 250℃ it remains safe even when a vehicle stands in the baking sun for hours.
However, we will have to be patient. Just because researchers have succeeded in developing a new fueling way does not mean that we can expect to see such vehicles on the road anytime soon. It will indeed be several years before this concept is turned into reality.
1. As a fuel, what is the advantage of hydrogen over oil?| A．Refilling empty tanks will be more convenient. |
| B．It is less likely to worsen global warming |
| C．More energy can be packed in the same space. |
| D．It will produce pure water for people to drink. |
| A．The practical difficulties to use hydrogen as fuel in small vehicles. |
| B．The detailed processes of adapting a strong tank in small vehicles. |
| C．The differences in fueling between large vehicles and small ones. |
| D．The tricks of building strong tanks in small vehicles. |
| A．inexpensive | B．powerful | C．convenient | D．environment-friendly |
| A．Powerpaste-driven vehicles sometimes move very slowly on the road. |
| B．Practical use of powerpaste-driven vehicles will not come very soon. |
| C．Powerpaste-driven vehicles can only work after being in the sun for hours |
| D．It will be years before the researchers work out the concept of powerpaste. |
3 . What if we had the power to control time, instead of moving from the past to the present to the future? What if we could jump, loop and travel through time in a machine? What if we could go wherever and whenever we pleased?
This ability would allow us to witness historic wonders, change decisions and see people from the past. We could right wrongs and stop wars from starting.
The mysterious puzzle of time has kept people debating its nature for hundreds of years. Science fiction writers have turned it into imaginative stories. Some scientists have even attempted to explain it using math. This math tries to make the dream of time travel come true.
The scientist Albert Einstein said that time and space are one thing. He called it “spacetime.” Einstein said that there are three dimensions in space: height, width and depth. A scientist named Hermann Minkowski added time as a fourth dimension.
Einstein introduced two ideas that have led to theories about the possibility of time travel. The first is relativity. The idea of relativity is that the force of gravity causes space to bend, which causes time to twist. The second idea focuses on special relativity. The idea is that a traveler moving super-fast through flat spacetime will enter the future. Einstein considered time “relative” because it is measured based on where we are on Earth or in space.
Stephen Hawking is a famous scientist. He believes that a time machine will never be built. If it were possible, he thinks we would already know. If a time machine could be built, how come no one from the future has invaded us?
The first science fiction story with this theme is The Clock That Went Backward by Edward P. Mitchell, which was published in 1881. Since then, thousands of books, films and television shows have explored the idea of time travel, in which some tools such as phones, watches, photographs and old books take travelers backward and forward.
Will time travel ever happen? Who knows? Most important is to keep your eyes open and have a sense of wonder.
1. What is the author’s purpose of writing the first paragraph?| A．To show time and space are connected. |
| B．To show people’s interest in time travel. |
| C．To draw readers’ attention to time travel. |
| D．To make people believe time travel is possible. |
| A．Time travel is possible in the future. |
| B．People can’t move faster than light. |
| C．Time travel is against scientific rules. |
| D．Spacetime is not a real thing in theory. |
| A．The first science fiction story. |
| B．Some tools used in time travel. |
| C．Edward P. Mitchell, the pioneer. |
| D．Different works about time travel. |
| A．cautious. | B．pessimistic |
| C．sceptical | D．optimistic. |
4 . For centuries, people have moved to and lived in cities. These urban centres are places to find work, friends and fun. It's no surprise that they continue to grow as more and more people flood in hoping to make the most of the chances they offer but adding to the congestion and pollution that already exist.
According to a report by the United Nations, 54 percent of the world's population lives in urban areas and it predicts that by 2050,this figure will have increased to around 70 percent. But as more and more people move from the countryside to the city to get better chances, they can end up with nowhere to live.
This is true in places such as Rio de Janeiro, where the people from the countryside can't rent or buy a home,and they end up building their own communities and houses on unoccupied land. These are called shanty towns— poor communities where the houses are built out of cheap materials—and often don't have any electricity or water supply.
These are, of course, not the future cities we want to see. Some serious urban planning is needed to make our cities of the future good, safe and modern places to live in. This involves improving the housing conditions, the chances for education and employment and so on.
Something urban planners are looking at now is the creation of“smart cities”. According to John Rossant, founder and chairman of the non-profit organisation New Cities Foundation, technology is the way forward. He thinks that it's generally accepted that “cloud computing, ubiquitous Internet, robust 5G networks etc, will change our cities”. He says technology is really “a game changer” in urbanization (城市化). It would collect large amounts of data about how a city is working and may improve how a city functions.
1. Why will a larger population be living in a city by 2050?| A．Because the government encourages the development of cities. |
| B．Because more people will have more children. |
| C．Because the countryside will disappear. |
| D．Because more people will move into the city to get more good opportunities |
| A．They have good quality housing built for poor people. |
| B．They are filled with people living under poverty. |
| C．They are built by the government. |
| D．They are developed and modern. |
| A．Traditional cities. | B．Future cities. |
| C．Smart cities. | D．Developing cities |
