Personality is to a large extent inherent——A-type parents usually bring about A-type offspring. But the environment must also have a profound 　1　, since if competition is important to the parents, it is likely to become a major factor in the lives of their children.
　　One place where children 　2　A-characteristics is school, which is, by its very nature, a highly competitive institution. Too many schools adopt the “win 　3　all costs” moral standard and 　4　their success by sporting achievements. The current passion 　5　making children compete against their classmates or against the clock produces a two-layer system, in which competitive A-types seem in some way better than their B-type fellows. Being too 　6　to win can have dangerous 　7　, remember that Pheidippides, the first marathon runner, dropped 　8　seconds after saying, “Rejoice, we 　9　.”
　　By far the worst form of competition in schools is the disproportionate emphasis on 　10　.It is a rare school that 　11　pupils to concentrate on those things they do well. The merits of competition by examination are somewhat 　12　, but competition in the certain knowledge of failure is positively harmful.
　　Obviously, it is neither practical nor 　13　that all A-youngsters change 　14　B's. The world needs A-types, and schools have an important duty to try to fit a child's personality to his possible future 　15　. It is top management.
　　If the preoccupation of schools with academic work was 　16　, more time might be spent teaching children surer values. Perhaps selection for the 　17　professions, especially medicine, could be made less by good grades in chemistry and more by such considerations as 　18　and sympathy. It is surely a 　19　to choose our doctors exclusively from A-type stock. B's are important and should be 　20　.______

A.towards

B.for

C.at

D.by