Question

阅读以下短文，根据各小题的具体要求，简要回答问题。

　　Researchers in the United States have discovered that the combination of daily exercise and a cup of coffee may help prevent skin cancer．

　　The scientists at Rutgers University in New Jersey say a low to moderate intake of caffeine combined with exercise can be good for health and prevent damage caused by the Sun's ultraviolet rays(紫外线)．

　　They have arrived at this conclusion after conducting a study on mice and suggest that a duo of caffeine and exercise appears to collude to kill off precancerous cells whose DNA has been damaged by radiation from the sun's UVB-rays．

　　Skin cancer is one of the most common cancers and is becoming more prevalent across the world；each year in the US, there are 1000, 000 new cases of non-melanoma skin cancer and 2000 deaths；in Britain, there are more than 65, 000 new cases of skin cancer．These cases are nearly curable if caught early enough．

　　For the study the researchers used groups of hairless mice, whose skin is as a result far more vulnerable(易受攻击的)to the sun．

　　One group were given caffeine to drink, equal two cups of coffee for humans, another group exercised on running wheel, while a third group both drank caffeine and ran；a fourth group, which served as a comparison, neither ran nor drank caffeine．

　　All of the mice were then exposed to lamps producing UVB radiation that damaged the DNA in their skin cells．

　　They were then examined for evidence of programmed cell death, also known as apoptolic(细胞凋亡), the process by which cells with badly damaged DNA destroy themselves as a natural defence against illness and infection．

　　The team of researchers found that compared with the UVB-exposed control group, the caffeine drinkers showed an increase of about 95 per cent in UVB-induced(诱发的)apoptosis, the exercisers showed a 120 per cent increase, while the mice that were both drinking and exercising showed a nearly 400 per cent increase．

　　One of the study's authors Dr．Allan Conney says if apoptosis takes place in a sun-damaged cell, its progress toward cancer will be aborted(夭折)．

　　The team say drugs which induce apoptosis are currently being researched as a method of preventing different types of cancer, but the combination of caffeine and exercise appears to have a similar protective effect．

1．Find in the passage a word closest in meaning to the underlined word“duo”．

2．Why didn't a group of mice exercise or drink caffeine?(回答词数不超过9个)

3．What is the purpose of writing the article?(回答词数不超过10个)

Answer 1

答案：
解析：

1．Combination． 　　2．Because they were used as comparison against other subjects/Because they served as a comparison． 　　3．To inform/introduce the result of a recent medical study．