Food safety is a problem in all places around the world and people in different areas of the world prepare foods in different ways. The WHO released (发布) five simple rules for preparing food in a safe way. They call these rules the “Five Keys to Safer Food”.

Key 1: Keep clean

    {#blank#}1{#/blank#}People should wash their hands often — before touching food and while they are preparing food. People should wash all surfaces and equipment used for preparing food.

Key 2: Separate raw (生的) and cooked

    Raw foods should not touch prepared foods.{#blank#}2{#/blank#}.

Key 3:{#blank#}3{#/blank#}

    People should cook eggs and meat especially carefully. These foods may carry more micro-organisms (微生物) than other foods. Food like soup must be boiled for at least a minute to make it be cooked completely. It is also important that people re-heat cooked food completely.

Key 4: Keep food at safe temperatures

    When people finish eating, they should keep the left food in a refrigerator below 5℃and shouldn't store it for too long. At room temperature, about 20℃, the amount of micro-organisms can increase very quickly. But temperatures above 60℃ or below 5℃ control the growth of micro-organisms.{#blank#}4{#/blank#}.

Key 5: Use safe water and raw materials

    {#blank#}5{#/blank#}. Damaged or old food may develop harmful chemicals as it gets older.

A. Cook completely

B. This key tells about the importance of washing

C. Eat healthily

D. They can live where we make food

E. People should use safe water and choose fresh foods

F. They cannot grow as quickly in a very hot or very cold environment

G. People should use separate equipment and tools for touching and preparing raw foods

    In its early history, Chicago had floods frequently, especially in the spring, making the streets so muddy that people, horses, and carts got stuck. An old joke that was popular at the time went something like this: A man is stuck up to his waist in a muddy Chicago street. Asked if he needs help, he replies,“No, thanks. I've got a good horse under me.”

    The city planners decided to build an underground drainage(排水) system, but there simply wasn't enough difference between the height of the ground level and the water level. The only two options were to lower the Chicago River or raise the city.

    An engineer named Ellis Chesbrough convinced the city that it had no choice but to build the pipes above ground and then cover them with dirt. This raised the level of the city's streets by as much as 12 feet.

    This of course created a new problem: dirt practically buried the first floors of every building in Chicago. Building owners were faced with a choice: either change the first floors of their buildings into basements, and the second stories into main floors, or hoist the entire bulidings to meet the new street level. Small wood-frame buildings could be lifted fairly easily. But what about large, heavy structures like the Tremont Hotel, which was a six-story brick building?

    That's where George Pullman came in. He had developed some house-moving skills successfully. To lift a big structure like Tremont Hotel, Pullman would place thousands of jackscrews(螺旋千斤顶) beneath the building's foundation. One man was assigned to operate each section of roughly 10 jackscrews. At Pullman's signal each man turned his jackscrew the same amount at the same time, thereby raising the building slowly and evenly. Astonishingly, the Tremont Hotel stayed open during the entire operation, and many of its guests didn't even notice anything was happening.

    Some people like to say that every problem has a solution. But in Chicago's early history, every engineering solution seemed to create a new problem. Now that Chicago's waste water was draining efficiently into the Chicago River, the city's next step was to clean the polluted river.

Having Breakfast or Not

    Will it matter if you don't take your breakfast? A short time ago, a test (试验) was given in the United States. People of different ages, from 12 to 83, were asked to have a test. During the test, these people were given all kinds of breakfast, and sometimes they got no breakfast at all. Scientists (科学家) wanted to see how well their bodies worked when they had eaten different kinds of breakfast.

    The results show that if a person eats a right breakfast, he or she will work better than if he or she has no breakfast. If a student has fruit, eggs, bread and milk before going to school, he or she will learn more quickly and listen more carefully in class. The result is opposite to what some people think. Having no breakfast will not help you lose weight (减轻体重). This is because people become so hungry at noon that they eat too much for lunch. They will gain weight (增加体重) instead of losing it. You will lose more weight if you reduce your other meals.

    Teenagers in America know that they'll possibly need technical skills to find good jobs, but a new survey reveals that interest in technology-related careers may be decreasing.

The percentage of boys aged 13 to 17 who are interested in science, technology, engineering and math —or STEM —careers dropped from 36 percent in 2017 to 24 percent this year, according to a survey by Junior Achievement USA. The amount of girls interested in STEM careers stayed unchanged at II percent.

    But the 1, 000 survey participants still named technology as one of two key skills that will be necessary to prepare them for their future careers.

    "Kids don' t understand how technology can be applied to careers in addition to computers, and maybe robotics, "said Tammera L. Holmes, president of aviation consulting firm AeroStar Consulting （航空资询公司）.“That's all they know, so they can't really translate that interest to career pathways."

    When Holmes was in high school, her mom sent her to an event that featured (以......为专题)the pilots from World War II. One of the pilots took her for a ride and let her take the wheel immediately that was the career for me." she said.

    Women remain outnumbered(超过) by men in fields like technology. For people working to increase the number of women in these areas, the lack of growth in girls interest in STEM careers is concerning.

    Teenage girls are more interested than their male classmates in running after careers in which they can help others, said Ed Grocholski from Junior Achievement. Even with all the programs aimed at increasing girls' interest in STEM, "I don't think we really talk that much about how we improve people's lives through STEM," Grocholski said.

    Society needs to do better at making those connections for kids, said Katherine Latham, founder of an engineering firm. She used civil engineering as an example of a career that will continue to be important.

    However, the fact that students know they will need tech skills in their future careers is encouraging.

    The second skill they said they need is relationship-building.

    "That's going to be the new type of engineers," Latham said.

    Reality TV show has been charged with making the nation silly, but a study suggests part of the show could be good for children.

    Massey University PhD student Jacinta Hawkins looked at the influence of TV programs on kids' health knowledge, attitudes and behavior. She said programs which showed overweight people on TV is making children say "I don't want to grow up like that'."

    The research was part of Ms Hawkins' paper on how schools improve health. She spoke to 92 children, ages from 7 to 13, from six Auckland primary schools to find out how they received information on nutrition and physical activity. Some said they learnt from TV news programs, but most of them mentioned reality shows such as Fat Chance, Honey We're Killing the Kids and Downsize Me.

    "Earlier studies had looked at the effect junk-food advertising had on children," Ms Hawkins said, "but messages within TV programs had not been explored. Children from the six schools largely recognized program content, rather than advertising, as a source of food and physical activity messages. They are learning habits of eating and exercise from TV programs. "

    The children also recognized that their parents had a role to play in shaping health behavior. Talking about Honey We're Killing the Kids, which shows how people will look if they continue with good habits, children said they developed attitudes from their family's habits. MMs Hawkins said children remembered what they had seen and thought it was the parents' duty to lead by example.

    More than 20 years ago, a skeleton called Little Foot turned up in a South African cave. The nearly complete skeleton was a member of the human family. Now researchers have freed most of the skeleton from its stony shell and analyzed the fossils (化石) and they say 3.67-million-years-old Little Foot belonged to a unique species.

    Researcher Ronald Clarke and his colleagues think Little Foot belonged to A. Prometheus (普罗米修斯南猿). Clarke works at the university of the Witwatersrand in Johannesburg South Africa. He studies fossilized humans and our relatives. Their foundings, published in four papers, have suggested the species A.Prometheus might have existed. Clarke has believed in that species for more than a decade, he found the first Little Foot's remains in a storage box of fossils in 1994. People began digging out the rest of the skeleton in 1997.

    Many other researchers instead argue that Little Foot likely belonged to a different species, which is known as A.africanus (南方古猿非洲种). Researcher Raymond Dart first identified A.africanus in 1924. He was studying the skull (头颅骨) of an ancient youngster called the Taung Child. Since then, people have turned up hundreds more A. africanus fossils in South African caves. Those include Sterkfontein, where Little Foot was found.

    The braincase is the part of the skull that holds the brain. And researchers found a partial braincase that Dart thought belonged to a different species in Makapansgat, one of those other caves. In 1948, Dart called this other species A. Prometheus, but he changed his mind after 1955. Instead, he said that braincase and another fossil at Makapansgat belonged to A.africanus. There was no A. Prometheus after all, he concluded.

    Clarke and his colleagues want to bring back the rejected species. They say Little Foot's distinctive skeleton, an adult female that is at least 90 percent complete, is solid evidence for it.