Eat healthier. Exercise twice a week. Read more books. Lose weight. We make the same resolutions(决心) every year, but most of us fail, dying out after only a few days or , at best, weeks. Even the most successful among us crash and burn when it comes to personal change. President-elect Barack Obama struggles to remove his cigarette habit. Professionals who help people make changes in their lives suggest the change is determined not by one's surroundings, but one's mind. Beginning with small goals or steps usually leads to a bigger payoff later, they say. But they caution that the experience is different for everyone. 'People are more likely to make positive changes in their lives not only when their friends do, but when their friends of friends do, and when their friends of friends of friends do,' said Nicholas Christakis, a professor of medical sociology at Harvard University. 'People are better able to make changes in their lives - lose weight, quit smoking, become happy - when they do this with a large number of other people, and so taking advantage of your social network ties can result in a magnification of your own efforts.' Jhonny Augustin understands that well. His resolution for 2008 was to shed 30 pounds from his 237-pound frame. But the change didn't come easily. He said,'I'm a huge procrastinator , I kept putting it off until tomorrow. I didn't get to do it until the summer.' However , Augustin got inspired when he saw his older brother working out. Today, Augustin weighs 190 pounds. “Of course, change can happen only if people don't set their expectations too high or try to tackle too many changes at once; one of the biggest mistakes we make is setting unrealistic goals, ”said Dalia Llera, a psychologist and associate professor of counseling and psychology at Lesley University. 'You can't accomplish in a few weeks what you haven't accomplished in a few years,' said Llera. 46.From the first paragraph we can infer that      . A.change for a person is challenging B.famous people have great determination C.most people don’t want to change themselves D.personal change is beyond belief 47.It is known from Nicholas christkis that      . A. making a change is easier with support from a cheerful group of friends B. social networks have great effect on one’s change C. people who have the same attitude often get together D. people’s mood can contribute to their efforts 48.The word “procrastinator” in Paragraph 4 refers to those who      . A. have great determination to make a change B. have no desire to do something great C. put off work especially because of laziness D. have habitual carelessness and laziness 49.According to the passage, Dalia Liera suggested that      . A. people should understand their goals well B. people should try their best to change themselves C. people should have confidence and positive habits D. people should start with setting small goals to meet 50.The passage is mainly about      . A. the reason why losing weight is so hard B. the effect of the positive change C. the attitudes towards change in life D. the ways of making a change