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 five simple rules for preparing food in a safe way. 1.

Key 1: Keep clean.

The first key tells about the importance of washing. People should wash their hands often—before touching food, while they are preparing food, and any time after they go to the toilet. People should wash all surfaces and equipment used for preparing food. 2.

Key 2: 3.

People should separate raw, or uncooked food from foods that are already cooked and foods that will not be cooked. People should store raw meat, chicken, and fish in containers, or in separate areas. Raw foods should not touch prepared foods.

Key 3: Cook completely.

People should cook eggs and meat, like birds, seafood, and animals, especially carefully. These foods may carry more micro-organisms 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 are finished with 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. 4. They cannot grow as quickly in a very hot or very cold environment.

Key 5: Use safe water and raw materials.

5. Damaged or old food may develop harmful chemicals as it gets older.

A.Eat cooked food immediately, while it is still hot.

B.They call these rules the “Five Keys to Safer Food.”

C.Separate raw and cooked.

D.People should use safe water and choose fresh foods.

E.Keeping everything clean helps people to avoid micro-organisms.

F.People should also protect cooking areas and food from insects and animals.

G.But temperatures above 60℃ or below 5℃ control the growth of micro-organisms.

Many of us remember being in awe(敬畏) when we saw cloned dinosaurs running wild in the film Jurassic Park. And the idea of using technology to revive(恢复) extinct species has long fascinated not only writers and directors, but scientists as well.

According to The Telegraph, woolly mammoths(长毛猛犸象), which featured in the popular Ice Age animated movie series, “may walk the earth once more” now that scientists have taken another step toward realizing a long-held dream—recreating their DNA.

Mammoths became extinct around 10,000 years ago. However, since the discovery of near-perfect preserved remains in Arctic permafrost(北极冻土带) in May 2013, a variety of research studies have been carried out since.

Geneticists from Harvard University analyzed DNA from the remains, looking for genes which separated mammoths from elephants, such as hairiness and ear size. They then used the results to reproduce exact copies of 14 mammoth genes. “It is the first time that mammoth genes have been alive—although so far it has only been done in the lab,” George Church, lead researcher of the project, told the Sunday Times.

Church then used a new technique which allows scientists to edit DNA carefully, replacing sections of elephant DNA with the mammoth genes. So “we now have functioning elephant cells with mammoth DNA in them,” he said.

However, Church ruled out the possibility of bringing the mammoths back to life via cloning from frozen remains. He said he “preferred to focus on rebuilding the full mammoth genome(基因组) by analyzing DNA from preserved remains and putting it into the cells of its closest living relative – the Asian elephant,” reported The Telegraph.

Church argued that the return of the woolly mammoth—or rather, the return of something very similar—could help bring back fragile(脆弱的) ecosystems. However, some scientists believe that bringing back the mammoth would be unethical.

Professor Alex Greenwood, an expert on ancient DNA, said: “We may face the extinction of African and Asian elephants. Why bring back another elephant from extinction when we cannot even keep the ones that are not extinct around?” he told the Sunday Times. “What is the message? We can be as irresponsible with the environment as we want. Then we’ll just clone things back?”

“Money would be better spent focusing on conserving what we do have than spending it on an animal that has been extinct for thousands of years,” he said.

1.We can learn from the article that ______.

A. cloned mammoths followed cloned dinosaurs to get revived

B. the technology to revive mammoth genes is already mature

C. George Church and his colleagues tried to reproduce mammoth DNA

D. Church and his team managed to list all the genes that separate mammoths from elephants

2.According to Church, what is the significance of his study?

A. It could help prevent the extinction of the Asian elephant.

B. It could help people better tell elephant DNA from mammoth genes.

C. It could help bring back some extinct species and save fragile ecosystems.

D. It could help bring mammoths back to life via cloning from frozen remains.

3.The underlined word “unethical” in Paragraph 7 is closest in meaning to ______.

A. unacceptable B. misled

C. impractical D. illegal

4.According to the article, Professor Alex Greenwood believes that _______.

A. there is no need to worry about the extinction of African and Asian elephants at present

B. it’s necessary to bring back species that are beneficial to human beings from extinction

C. the return of the woolly mammoth would help to balance ecosystems

D. it’s more important to protect present species than to bring back extinct ones

About 1966 or so, a NASA (美国航空航天局) team doing work for the Apollo moon mission (任务) took the astronauts near Tuba City. There the landscape of the Navajo Reservation (保留地) looks very much like the lunar surface. Among all the trucks and large cars were two large figures that were dressed in full lunar space suits.

Nearby a Navajo shepherd (牧羊人) and his son were watching the strange creatures walk about, occasionally being watched over by other NASA workers. The two Navajo people were noticed and approached by the NASA people. Since the shepherd and his son did not know English, they asked the NASA people who the strange creatures were. The NASA people told them that they were just men that were getting ready to go to the moon. The shepherd became very excited and asked if he could send a message to the moon with the astronauts.

The NASA officials thought this was a great idea so they provided a tape recorder. After the man gave them his message, they asked his son to translate. His son would not.

Later, they tried a few more people on the reservation to translate and every person they asked would chuckle (偷偷地笑) and then refuse to translate. Finally, with cash in hand someone translated the message,

“Watch out for these guys, they have come to take your land!”

1.The appearance of the Navajo Reservation is very similar to that of ______.

A. the Tuba City B. the moon

C. the NASA research center D. the Apollo moon mission

2.When the older Navajo heard that the men in front of him were going to the moon, he ______.

A. felt frightened and ran away quickly

B. chatted excitedly with the NASA workers

C. got on the modern trucks and large vehicles for fun

D. tried to say something to the moon creatures

3.The son did not translate the words his father said because ______.

A. he had trouble in understanding his father

B. the words his father used were too difficult to be translated

C. his father was sending a warning against the NASA people

D. he believed that the NASA workers could understand their language

4.According to this passage, we can know that the shepherd was ______.

A. patient and brave B. foolish and impolite

C. humorous and intelligent D. knowledgeable and talkative

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