（复旦大学2011年试题） A considerable amount of medical research is aimed at identifying risk factors for disease. The rationale behind this work is that where people are informed of their risk, they will happily change their behavior to lower that risk.【1】this is certainly a reasonable assumption, it turns out that things are not quite that and straightforward. First of all, health is not necessarily a top priority in everyone’s life and, for these people, changing behavior in the interests of health may interfere【2】other, more important matters. Second, the benefits to be derived【3】such changes rarely are immediate or obvious. Usually, improvements in health take place over long periods of time and are quite subtle.【4】, we are all so bombarded with information about the thousands of health hazards to which we are exposed【5】most of us "time out" much of this information. This latter issue is compounded by the fact that much of new information to which we are exposed through the media is exaggerated and, as often as not, is contradicted later by even "newer" information. For these and other reasons, simply knowing about a risk does not necessarily ensure that people will take appropriate steps to【6】it. 【7】when people want to change their behavior, this is not easy to do. For example, the overwhelming majority of smokers in this country want to quit, but【8】great effort very few are able to do so. Most smokers acknowledge, at some level, that health hazards are associated with smoking and most wish that there were a and painless way to stop.【9】, the number of people who want to lose weight is very large, but few of these people are able to do it and even【10】are able to maintain such weight losses. 【5】