2013年6月大学英语四级考试已结束，本次考试为多题多卷，新浪教育[微博]频道第一时间收集整理不同版本试题，供考生参考，以下为英语四级完形填空答案。

　　2013年6月英语四级完形填空答案：

　　Part V Cloze

　　The human brain is the most complex structure on the universe. It contains 67roughly 100 billion nerve cells, each of 68which has thousands of connections with each other. Their interaction 69controls each 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 73expeeted in 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 78defects in genes that play a role in development. Half of all genetic 79diseases affect the nervous system. The brain can only reach its full 80capability through interaction with its 81surroundings. Researchers are examining the interaction of genes and 82experiences with regard to the expression and 83fine-tuning of nerve circuits in the brain. How do nerve cell 84processes find their goal? How do different brain areas develop? How do perceiving85 functions mature? 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。