【正文】 though a single ant alone in the water will struggle to survive. “They have to stay together as a colony to survive.” Nathan Mlot said. Fire ants and water don’t mix. The ant’s hard outer shell, naturally repels water. A drop of water can sit on top of the ant like a backpack. When an ant does end up underwater, tiny hairs on its body can trap bubbles of air that give the bug a boost up (托起 ). To investigate the science behind the antraft, the scientists placed hundreds or thousands of ants at a time in the water. A group of ants took about 100 seconds, on average, to build a raft. The researchers repeated the experiment multiple times. Each time, the ants anized themselves the same way, creating a raft were flexible and strong, staying together even when the researchers pushed the rafts underwater. The scientists then froze the rafts in liquid nitrogen and studied them under powerful microscopes to figure out how the ants kept everyone safe and the water out. The team found that some ants used their jaws to bite other ants’ legs. Other ants joined their legs together. Thanks to these tight bonds, say the scientists, the ants did a better job at keeping the water away than any one ant could do on its own. By working together, thousands of ants can stay alive in the face of a crisis like a flood by using their own bodies to build a boat. 46. When flood es, fire ants . A. will run away separately B. find a hole to hide themselves C. bine themselves into a raft D. climb onto boats on the water 47. What makes fire ants stay afloat? A. Tiny hairs on their body. B. Their hard outer shell. C. Their slippery skin. D. Their backpack on its body top. 48. After scientists put fire ants into the water, they . A. built a raft in 100 minutes B. anized themselves into a flexible raft C. anized themselves in different ways D. liked to look for the food of pancakes 49. The story of fire ants proves the importance of . A. practice B. calmness C. cooperation D. speed 50. The purpose of writing this text is to introduce . A. how fire ants react in face of danger B. fire ants’ differences from mon ants C. fire ants’ ability to live underwater D. the building ability of fire ants D I am truly frustrated by the way my teenage children behave with me. It is a roller coaster(過山車 )ride each day coping with their moodiness and argumentative nature. But I do appreciate the courage they project at times and goals they undertake that make me feel that they really aim high in life.” This could be the feeling of most parents with teenage children. I can understand and empathize with these parents, but they are not alone. Children start their journey into the broad world and are greatly influenced by what others have to say especially their peers that they consider more close than even their parents and family at times. The brains teenagers or children in the ages of 13 to 19 undergo(經(jīng)歷 )a lot of changes that bring about these effects that most parents like us fail to understand. One of the prominent changes is what takes place due to the beneficial pruning (修剪 )that takes place in the neutral branches of the prefrontal cortex(前額皮質(zhì) ). All these changes ultimately help build clear judgment, plan and control impulses skills. It is best that we just recollect how we behaved as a teenager and you would definitely e across some of our mums that support their teenage grandchildren and say we were much worse. I can empathize with such parents as probably our parents are getting a chance to air out their feelings that they could probably never do when we were teenagers.( taking a positive look by realizing that it is a part of the growing process would help.) We may tell our teenage children to have confidence in their abilities and not be influenced by what others say of them, but this anxiety of what society says of them can be overwhelming. It could be real enormous pressure that teens can never e about telling parents, but it would pay to build up trustworthy relationships with them. This would help keep a watch and monitor some of their inappropriate activities and avoid their getting into trouble due to peer pressure and emotional vulnerability. 51. What is the best attitude for parents to treat children’s changes? A. Leaving them alone. B. Thinking them crazy. C. Under