The unhealthy ingredients and low nutrition content of the food can make you less active and lazy, new research shows. No surprises there.【C1】______, what is more shocking is that the energy-weakening effects of a junk food diet can persist,【C2】______after you switch to a healthy【C3】______. Two groups of female rats were fed different diets by researchers for a six-month period. One group ate unprocessed foods such as corn and fish meal【C4】______the other ate a diet【C5】______to imitate junk food; high in sugar, and lower in【C6】______. While understandably the group eating the 'junk food' diet gained more weight than the other, they also【C7】______from fatigue and became less active and less【C8】______—ie: lazier. In fact, those rats fed junk food took twice as many, and longer breaks during tasks than the rats eating a healthy diet, even tasks which【C9】______rewards. What is even more【C10】______is that switching these rats back onto a nutritious diet at the end of six months for nine days didn't seem to reverse their weight gain or their 'learnt' laziness. This could suggest that while an【C11】______case of bad food—say on holiday, will not have too much of a【C12】______effect if you generally eat a good diet and lead a healthy lifestyle. But those who eat a poor diet【C13】______the long term may actually become lazy and fatigued, as well as gaining weight and suffering the health consequences【C14】______being overweight. The research shows that switching【C15】______a healthy diet in the short term is unlikely to be【C16】______to reverse any of the side effects of a diet high in junk food. "Overweight people are often regarded as lazy and lacking【C17】______," says Blaisdell, a professor of psychology at UCLA "We【C18】______our results as suggesting that the idea commonly【C19】______in the media that people become fat because they are lazy is wrong. Our data suggest that diet-induced obesity is a cause,【C20】______an effect, of laziness. Either the highly processed diet causes fatigue or the diet causes obesity, which causes fatigue."
单选题
【C1】
【正确答案】
C
【答案解析】解析：上句提到食物中含不健康成分以及营养含量低会有不良影响，而且这一现象司空见惯(No surprises there)，空格后则说what is more shocking(更令人更加震惊的是)，这与No surprises语义相反，所以应填入表转折关系的连词。选C项However“然而”。
单选题
【C2】
【正确答案】
D
【答案解析】解析：前半句提到垃圾食品饮食方式导致的精力减退效应会长时间持续，主语what is more shocking表示这种效应超出了人们的预期，D项even可用来加强语气，表示“即使，甚至连……都”，用于强调after引导的时间状语从句。
【答案解析】解析：根据表对比的while来判断，if条件状语从句中的generally eat a good diet(平时饮食健康)应与an．．．case of bad food存在对比。因此空格处所填的词语语义和generally相反并能说明插入语holiday的性质，故B项occasional“偶尔的”。
【答案解析】解析：定语从句中需填入一个介词与the long term构成的短语作为eat a poor diet的时间状语。A项over表示“在……期间”，over the long term表示“在长期内”，该句意为对于在长期内饮食不健康的人而言。
单选题
【C14】
【正确答案】
B
【答案解析】解析：长期饮食不健康的人很有可能变得懒惰、疲劳(lazy and fatigued)、体重增加(gaining weight)，还要承担因此而产生的后果(consequences)。此空格需填入的短语与being overweight构成consequences的后置定语，说明两者的关系。B项associated with“与……有关”，表明饮食不健康与超重有关。
单选题
【C15】
【正确答案】
C
【答案解析】解析：此处填入与switching(转换)搭配的介词，宾语是a healthy diet，与上一段第一句switching these rats back onto a nutritious diet语义对应。switch to表示“转变成”符合语义逻辑。故选C项to。
单选题
【C16】
【正确答案】
A
【答案解析】解析：本段开头提到研究中观察到那些吃了6个月的垃圾食品的小白鼠，切换回健康营养的饮食方式9天后，仍然不能扭转体重增加以及慵懒的状态。本句与上文语义呼应，阐述小白鼠实验中得出的结论：短期内不能逆转食用大量垃圾食品导致的副作用(reverse any of the side effects)，因为短期内给身体补充健康的食物是不够的，故选择A项sufficient“足够的”。