The poaching（偷猎）, or illegal killing, of rhinos(犀牛) in South Africa is growing worse each year．The government recently reported that a record number of rhinos were poached in 2015，a year which had more rhino killings in South Africa than ever before.

    The World Wildlife Fund，or WWF，says about 20, 000 rhinos live in South Africa．That is more than 80 percent of the rhinos in the world．Edna Molewa，South Africa's Environment Minister，says, “During 2015，we are sad to say this，1,215 rhinos were killed．This is a rise in the number of poached rhinos from 1,004 in 2014 and indeed very worrying.”

    The animals are hunted for their horns(角)．Many people in Asia believe the horn has curing power，which drives poachers， at all costs，mad for more horns． But there is no scientific evidence for this belief．The horn is made of keratin(角蛋白)．That is the same thing as human hair，fingernails and toenails.

    Ms．Molewa said 386 suspected poachers were arrested last year，an increase from the year before．But rhino protection workers say poachers often go unpunished after arrest． South Africa's legal system is ineffective． Ms． Mo1ewa said more needs to be done and South Africa is taking strong measures to protect rhinos．The efforts include moving some of the animals to secret places in neighboring countries. “Now approximately 100 rhinos have been moved to neighboring states in the SADC region during 2015 and 200 more rhinos will be moved this year,” Molewa said.

    Jo Shaw，the rhino program manager at the WWF，said， “We're talking about a loss of a hundred rhinos a month，or more than three a day．We really need to see effective action not just at a national level but internationally．” She says officials should find the criminal groups responsible for the poaching and punish them. Government officials are to meet in Botswana in March at the Inter-governmental Conference on Illegal Wildlife Trade.

    Teachers' Day is, interestingly, not celebrated on the same day all over the world. In some countries it is marked by a holiday; in others it is a working day.

    International Teachers' Day is celebrated on October 5. Being held ever since 1994, it is in honor of teachers' organizations worldwide. Its aim is to encourage supports for teachers and to meet the needs of students.

China — In 1939, Teachers' Day was set for August 27, Confucius' birthday. In 1951, the celebration was stopped. However, it was founded again in 1985, and the day was changed to September 10.

India — Teachers' Day is celebrated on September 5 in honor of Dr. Sarvepalli Radhakrishnan, the second president of India, whose birthday falls on that day.

    Russia — In Russia, Teachers' Day was celebrated on the first Sunday of October between 1965 and 1994. Since 1994, the day is observed on October 5, just the same day as World Teachers' Day.

    The US - In the US, Teachers' Day is non-official holiday. It is celebrated on the Tuesday of the first full week of May. A number of activities are organized in schools to honor teachers. The celebrations can continue for the whole week of May.

Thailand — In Thailand, National Teachers' Day is celebrated every year on January 16. The first Teachers' Day was held in 1957. The day is a holiday in schools.

    German engineers Gottlieb Daimler and Karl Benz built the first successful gasoline engines in 1885.After 1900, however, the United States became a leader in automobile production.

    The first cars were handmade and very expensive. Only people in rich cities could afford them. The first company to make gasoline cars in the U.S. was the Duryea Motor Wagon Company. Then, in 1901, Ransom E. Olds Began mass-producing his car, the Oldsmobile. In 1913Henry Ford made great strides in the mass production of cars by using an assembly line in his factory. Mass production meant that each car was less expensive to make. Now car ownership was affordable for the average person. By 1916there were more than one million cars in the United States.

    The automobile gave people the freedom to travel anywhere there were passable roads. Families that lived great distance apart could travel by automobile to visit each other. People could visit places they had never seen before.

    Before the mass production of cars, people lived close to work. Their means of transportation included walking, riding a bicycle, using a horse and carriage, or taking a train. The automobile gave people the ability to live farther away from work. The result was that gradually people moved out of the cities to the less crowded suburbs.

    The automobile industry created millions of jobs. The jobs were not just in the auto factories, where the cars were assembled. Workers were needed to make auto parts, run gas stations and repair shops, and work at new motels and restaurants that served people who traveled by car. Jobs became available at car rental companies. People were needed to build roads. These jobs and many others still exist because of the automobile.

    Throughout much of human history, man has been the measure of many, if not all, things. Lengths were divided up into feet and smaller units from the human hand. Other measures were equally characteristic. Mediterranean traders for centuries used the weight of grains of wheat to define (定义) their units of mass. The Romans used libra, forerunner of the pound, by referring to the weight of a carob (角豆树) seed.

    The sizes of similarly named units could also differ. The king's foot, used in France for nearly 1, 000 years after its introduction by Charlemagne in around 790 AD, was, at 32.5cm, around a centimeter shorter than the Belgic foot, used in England until 1300.Greek, Egyptian and Babylonian versions of water in a fixed container varied from one another by a few kilos, Nor was there agreement on such things within countries. In France, where there was no unified (统一的) measurement system at the national level, the situation was particularly terrible. The lieue (former measure of distance), for example, varied from just over 3 km in the north to nearly 6 km in the south.

    Although John Wilkins, an Englishman, first put forward a decimal system (十进制) of measurement in 1668, it was the French who in 1799 made it law. The Système International d'Unités (SI, or the metric system, as it is better known) developed from it and became the official measurement in all countries except Myanmar, Liberia and the United States. Now the International Bureau of Weights and Measures in Paris is set to give the metric system its biggest shake-up yet.

    At a meeting in Versailles, France, on November 16th, 2018, the world's measurement bodies are almost certain to approve a decision that will mean four out of the seven base SI units, including the kilogram, will follow the other three, including the metre, in being redefined in terms of the values of physical constants (物理常数).Each of the chosen constants has been measured incredibly precisely, which would mean that from May 20^th 2019 the constants will themselves be fixed at their current values for ever. Any laboratory in the world will then be able to measure, for example, the mass of an object as precisely as the accuracy of their equipment will allow.

    Some colors people see late at night could cause signs of clinical (临床的) depression. That was the finding of a study that builds on earlier study findings. They show that individuals who live or work in low levels of light overnight can develop clinical depression. Doctors use the word "clinical depression" to describe severe form of depression. Signs may include loss of interest or pleasure in most activities, low energy levels and thoughts of death or suicide.

    In the new study American investigators designed an experiment that exposed hamsters (仓鼠) to different colors. The researchers chose hamsters because they are nocturnal which means they sleep during the day and are active at night.

    The animals were divided into four groups. One group of hamsters was kept in the dark during their night-time period. Another group was placed in front of a blue light a third group slept in front of a white light while a fourth was put in front of a red light.

    After four weeks the researchers noted how much sugary water the hamsters drank. They found that the most depressed animals drank the least amount of water.

    Randy Nelson heads the Department of Neuroscience at Ohio State University. He says animals that slept in blue and white light appeared to be the most depressed. "What we saw is that these animals didn't show any sleep uneasiness at all but they did mess up biological clock genes and they did show depressive sign while if they were in the dim (微弱) red light they did not."

    He notes that photosensitive (感光) cells in the eyes have little to do with eyesight. He says these cells send signals to the area of the brain that controls what has been called the natural sleep-wake cycle.

    He says there's a lot of blue in white light. This explains why the blue light and white light hamsters appear to be more depressed than the hamsters seeing red light or darkness.

When it comes to travel, sometimes wandering is one of the most exciting things you can do. In a time when travellers are both more adventurous and eco-conscious than ever, it's no surprise that there's a wealth of new vocabulary to describe how we travel, when we travel and how the experience makes us feel. Here are eight of our favourite travel words that you may not have heard before.

We've kicked off a blog with the staycation, "a holiday in one's own country". The term first became popular in the mid-2000s, when the global financial crisis meant people had less income to spend on flash holidays and instead searched for cheaper local choices. Since 2020, the staycation is experiencing a revival (复兴). Benefits of staycations include cheaper travel costs, no spending hours in the airport and, of course, no need to worry about whether your passport expired (过期) last year.

Once upon a time, if you wanted to meet new people on your travels, you could stay at a hostel or with a host on Airbnb. Now, you can couch surf. And not just in "the staying at various friends' houses until you find a new place to rent" sense: couch surfing is quickly becoming a hot new travel trend. Travellers can now choose to couch surf all across the world via a website which treats travel as a cultural exchange, allowing people to connect with willing hosts and crash on their sofas.

Given that single-use and climate strike were selected as the Collins 2018 and 2019 Words of the Year respectively, it's clear that the climate crisis is very much on everybody's mind. This desire to make more sustainable choices is also affecting the way we spend our vacation days. Ecotourism is another popular travel trend, defined as tourism that is designed to contribute to the protection of the environment. Examples of ecotourism include ditching short-haul flights, staying at eco-friendly resorts, or booking a staycation.