Read the article and select the best answer. Article: Ants have a reputation for strength,organization and teamwork.But researchers have now discovered that a key secret to the success of ants is their ability to identify the importance of age in the work place. A study of Gentral American leaf-cutter ants has shown that the younger and stronger members are give the toughest job of cutting therough the leaves they harvest.Their sharp youn teeth do this job effectively,but as they get older their teeth become relatively worn and _ . But rather than being retired or abandoned by the group,the ageing ants are given a new role more suyted to their physical abilities.They become carriers and teansport the leaves back to the kingdom where they are harvested for food. The findings by researchers from the University of Oregon and the Oregong State University support previous research showin the survival of a leaf-cutter kingdom depends on the efficiency of is workers. "Cuting leaves is hard work,"said Dr.Robert Schofield,who led the research team."Much of the cutting is done with a V-shaped blade between teeth on their jaws.This blade starts out as sharp as the sharpest razor blade that humans have developed."But over rime the teeth become blunter and the cutting job slows down.The team estimated that,because of this age-related wear,a colony spent twice the energy cutting leaves than it would if all the ants had sharp blades.Its findings support the idea that wear and break can be significant problems for insects as well as largre animals. Like humans,leaf-cuttre ant recognize that older members of the group can still make a worhwhile contribution to society."This study shows an advantage of social living that we are familiar with,"said Dr.Schofield. Question: What can be the best title for the passage? Options: A: The key secret to the success of ants B: The developed structure of ant colony C: The most challenging job for leaf-cutter ants D: No V-shaped blade,no success of ants
A

Read the article and select the best answer. Article: Chinese students aren't the only ones who have a sleep loss problem. In Australia, teenagers are also missing out on, on average, one hour's sleep every night during the school week. Organized activities and homework push bedtimes later, the first large-scale Australian study of children's sleeping habits has revealed . Their sleep deprivation is enough to cause "serious drop-offs in school performance, attention and memory", and governments should consider later or flexible school start times, said the study's leader, Tim Olds. ks5u His survey, of more than 4,000 children aged 9 to 18, found those who slept least did not watch more television but spent their time socializing with family or friends or listening to music. "Almost all children get up at 7 or 7:15 -- they have to get to school on time," said Olds. He favors a later start over an earlier finish because he believes organized sports and activities would still consume the latter end of the day. Olds' research also establishes lack of sleep as a cause of weight gain in children, and a possible source of future problems with depression, anxiety and increased susceptibility to illness. It was already known that overweight children sleep less, but Professor Olds found sleep duration was strongly linked to weight across the full range of body sizes. The thinnest children sleep 20 minutes more than the _ . This showed being overweight had no specific effect on sleep patterns, and it was more likely that shorter sleep times stimulate appetite and make kids hungry. The US National Sleep Foundation says teenagers aged 13 to 18 need eight to nine hours' sleep a night. Younger school-aged kids need 9 to 11 hours. On that basis, Professor Olds said, half of Australian children are under-sleeping on weekdays and a quarter on weekends. Question: Which of the following statements is TRUE? Options: A: Australian students usually take part in activities in the afternoon. B: More students are short of sleep on weekends than on weekdays. C: Being overweight has an effect on the length of the sleeping time. D: The survey suggests that teenagers need 8-9 hours' sleep a night.
A

Read the article and select the best answer. Article: The crowd cheered as the young man walked across the stage to receive his award as the company's top producer. He looked over the audience and trembled, and there was a clear pause that brought a silence to the room. It took him a moment to control himself. "The last three months hit me pretty hard," he began. "And I feel the need to share a piece of my story though I'm not sure why. A friend called me about his new marketing system, an outbound fax service that could reach thousands of potential customers at very little cost. I checked it out, got excited and accepted it. After thousands of faxes, it seemed that what I did was illegal . I was punished a dollar for every one sent out. The crowd was surprised. "I failed to do proper research, and didn't pay attention to the details. Now I am heavily in debt. As some of you know, I recently move up here from down south. I stored my stuff in my old office, which I closed down. When I drove back to pick it all up, I found that everything except my computer and the clothes I brought with me was gone." He continued, "I drive a sports car. I love that car. One day while driving it, I stepped on the accelerator , lost control at 85 miles an hour, and hit the guard rail. I damaged my car very badly." "In three months, I got charged, lost everything I owned, and damaged my car. We all face challenges," he smiled. "I guess I wanted to share mine with you. Thanks for listening. " He left to a standing ovation . Standing in the back of the room, I realized how much respect that young man earned. He faced his fear, publicly admitted his mistakes and never gave up, in spite of the difficulties. That day, he won much more than a trophy . Question: The young man told his experiences perhaps to _ . . Options: A: encourage others to face challenges bravely B: let the audience forgive him C: show his misunderstanding of the law D: complain about being treated unfairly
A