题目

掘井导致草原破坏的原因是 A．过度樵采 B．过度放牧 C．过度开垦 D．水资源利用不当 答案：D 解析: 人们为了解决干旱地带人畜用水问题而掘井，人畜活动必然会以水井为中心，从而严重破坏草原植被，导致荒漠化在干旱半干旱地区迅速蔓延。For thousands of years, people have been debating the meaning of happiness and how to find it.  From the ancient Greeks and Romans to current day writers and professors, the debate about happiness continues. What makes someone happy? In what parts of the world are people the happiest? Why even study happiness? The Greek philosopher Aristotle said that a person's highest happiness comes from the use of his or her intelligence. Religious books such as the Koran and Bible discuss faith as a form of happiness. The British scientist Charles Darwin believed that all species were formed in a way so as to enjoy happiness. People throughout history may have had different ideas about happiness. But today, many people are still searching for its meaning.How do you study something like happiness? You could start with the World Database of Happiness at Erasmus University in Rotterdam, The Netherlands. This set of information includes how to define and measure happiness. Some findings are not surprising. For example, the database suggests that married people are happier than single people. People who like to be with other people are happier than unsocial people. But other findings are less expected: People with children are equally happy as couples without children. And wealthier people are only a little happier than poorer people. Positive psychology is the new term for a method of scientific study that tries to examine the things that make life worth living instead of life's problems. Traditional psychology generally studies negative situations like mental suffering and sickness. But positive psychology aims to study the strengths that allow people and communities to do well. There is also an increasing amount of medical research on the physical qualities of happiness. Doctors can now look at happiness at work in a person's brain using a method called magnetic resonance imaging (核磁共振成像), or MRI. For example, an MRI can show how one area of a person's brain activates when he or she is shown happy pictures. A different area of the brain becomes active when the person sees pictures of terrible subjects.46. What can be inferred from the first paragraph?  A. People are searching for the meaning of happiness.   B. Happiness is an everlasting topic for discussion.  C. Current day scholars are debating about how to make people happy.   D. People have begun to realize the importance of understanding happiness. 47. The Bible tells us happiness comes from _________.A. the application of one's intelligence    B. the strong belief in religionC. a certain degree of good faith           D. the trust in one's ability48. The findings of the database imply that couples without children are _________.A. as happy as people with children    B. less happy than people with childrenC. happier than unsocial people          D. a little happier than wealthier people49. As an approach of scientific study, positive psychology focuses on ________.A. mental suffering                                    B. psychological sicknessC. examining what makes life worth living    D. strengths that enable people to succeed50. MRI is used in the study of happiness in order to __________.A. find out the physical quantities of happiness    B. look at the images formed in people's brainC. study the reaction of the brain to happiness     D. understand the pictures of terrible subjects