2013年6月英语四级完形填空答案(卷一)

　　2013年6月大学英语四级考试已结束，新东方在线第一时间收集整理试题及参考答案，以下是2013年6月英语四级完形填空答案(卷一)供考生参考。

　　The human brain is the most complex structure on the universe. It contains 67roughly100 billion nerve cells, each of 68whichhas thousands of connections with each other. Their interaction 69controlseach of the body’s functions, allows thoughts, perceptions, memories, feelings, and also movement and 70communication. Understanding just how the brain works, in health or in sickness, is one of the 71greatest challenges of our time. What is determined by genes, what is formed by experience? Scientists are investigating all 72aspects of the nervous system. Great progress can be 73expeetedin visualizing and modeling brain functions, as well as in research into their biological basis. Today, it is 74assumed that 30 to 50 percent of human genes exercise their function 75chiefly in the brain. This gives an 76indication of the complexity of the genetic control and 77development.The cause of many nerve diseases lies in 78defectsin genes that play a role in development. Half of all genetic 79diseasesaffect the nervous system. The brain can only reach its full 80capabilitythrough interaction with its 81surroundings. Researchers are examining the interaction of genes and 82experienceswith regard to the expression and 83fine-tuning of nerve circuits in the brain. How do nerve cell 84processesfind their goal? How do different brain areas develop? How do perceiving 85 functionsmature? Thanks to research, the prevention and cure of may brain diseases seems possible for the first time. Better knowledge of the way the brain processes 86information could, moreover, make new computers possible.