Ôn thi Tốt nghiệp THPT môn Tiếng Anh (Đề 14)

Three scales of temperature, each of which permits a precise measurement, are in current use: the Fahrenheit, Celsius, and Kelvin scales. These three different temperature scales were each developed by different people and have come to be used in different situations.

The scale that is most widely used by the general public in the United States is the Fahrenheit scale. In 1714, Daniel Gabriel Fahrenheit, a German physicist who was living in Holland and operating an instrument business, developed a thermometer and the temperature scale that still carries his name. His original scale had two fixed points: 0° was the lowest temperature and 96° was what he believed was the normal temperature of the human body. Based on this scale, he calculated that the freezing point of water was 32°. In later studies, it was determined that the boiling point of water was 212°. The Fahrenheit scale came to be accepted as the standard measure of temperature in a number of countries. Today, however, the United States is the only major country in the world that still uses the Fahrenheit scale.

The scale that is in use in many other countries is the Celsius scale. Anders Celsius, a Swedish astronomer, developed a thermometer in 1741 that based temperatures on the freezing and boiling temperatures of water. On the thermometer that Celsius developed, however, 0° was used to indicate the boiling temperature of water, and 100° was used to indicate the freezing temperature of water. After his death, the scale was reversed by a friend, the biologist Carl von Linne. On the new scale after the reversal by von Linne, 0° indicated the freezing temperature of water, and 100° indicated the boiling temperature of water. At around the same time, a similar thermometer was being developed in France. After the French Revolution, the scale developed in France was adopted as part of the metric system in that country under the name centigrade, which means "a hundred units," and from there it spread worldwide. In 1948, an international agreement was made to rename the centigrade scale the Celsius scale in honor of the scientist who was first known to use a 100-degree scale, though it should be remembered that the scale that Celsius actually used himself was the reverse of today's scale.

A third scale, the Kelvin scale, is generally used today for scientific purposes. This scale was first suggested in 1854 by two English physicists: William Thomson, Lord Kelvin and James Prescott Joule. The Kelvin scale defines 0° as absolute zero, the temperature at which all atomic and molecular motion theoretically stops, and 100° separates the freezing point and boiling point of water, just as it does on the Celsius scale. On the Kelvin scale, with 0° equal to absolute zero, water freezes at 273°, and water boils at a temperature 100° higher. The Kelvin scale is well suited to some areas of scientific study because it does not have any negative values, yet it still maintains the 100° difference between the freezing point and boiling point of water that the Celsius scale has and can thus easily be converted to the Celsius scale by merely subtracting 273° from the temperature on the Kelvin scale.

Florists, personal trainers, professors, and nutritionists all have healthy jobs according to research. There are many reasons for this. A florist, for example, sells flowers and plants to customers. This is very relaxing work. A personal trainer, on the other hand, is usually very fit. He or she trains other people to lose weight and to keep fit.

However, research also shows that some jobs are 'unhealthy'. They cause a lot of stress and worry. For example, a taxi driver drives all day. He often faces traffic jams and difficult passengers too. A firefighter puts out dangerous fires and sometimes saves people from burning buildings.

Most people are looking for the perfect job. They want a job that is interesting, with a good salary and not much stress. However, it is difficult to get everything. Healthy, relaxing jobs are usually not very well paid. On the other hand, people with stressful jobs often get good salaries. For example, the head of a big company gets a lot of money, but he or she does not always have good health, or the time to enjoy life.

(Adapted from New Headway Academic Skills by Richard Harrison)

Urban development is having a direct impact on the weather in many cities worldwide. It has been noticed that the difference (27) ________ temperature is usually greater at night and the phenomenon occurs in both winter and summer. Experts agree that this is due to urban development, when open green spaces are replaced with asphalt roads and tall brick or concrete buildings. These materials retain heat generated by the Sun and release it through the night. In Atlanta, in the US, this has even led to thunderstorms (28) ________ occur in the morning rather than, as is more common, in the afternoon.

Large cities around the world are adopting strategies to combat this issue (29) ________ it is not uncommon to find plants growing on top of roofs or down walls of large buildings. In Singapore, the government has (30) ________ to transform it into a "city within a garden" and, in 2006, they held an international competition calling for entries to develop a master plan to help bring this about. One outcome was the creation of 18 "Supertrees"-metal constructions resembling very tall trees. Each one is a vertical freestanding garden and is (31) ________ to exotic plants and ferns. They also contain solar panels used to light the trees at night and also containers to collect rainwater, making them truly self-sufficient.