单项选择题

TEXT D
The world has spent on preparation for war more than $112 billion a year, roughly $450 per head for every man, woman, and child in the world. Let us consider for a moment what could be done with this sum of money if it were spent on peace and not on war. Some of it, at any rate, in the more prosperous countries, could be spent on the reduction of taxation. The rest should be spent in ways that will, at the same time, be of benefit to mankind and a solution to the economic problem of change from war industry to the expansion of peace industries. As to this expansion, let us begin with the most elementary of all needs, namely, food. Today, the majority of mankind suffers from undernourishment, and in view of the population explosion, this situation is likely to grow worse in the coming decades. A very small part of what is now being spent upon weapons would improve our predicament. Not only could the American surplus of grain, which was for many years uselessly destroyed, be spent in relief of famine, but, by irrigation, large region now desert could be made fertile, and by improvement in transport, distribution from regions of excess to regions of scarcity could be helped.
Housing, even in the richest countries, is often disastrously inadequate. This could be relieved by a tiny fraction of what is being spent on missiles. Education everywhere, but especially in the newly liberated countries of Africa and Asia, demands an expenditure many times as great as that which it receives now. But it is not only greater expenditure that is needed in education. If the terror of war were removed, science could be devoted to improving human welfare, instead of to the invention of increasingly expensive methods of mutual killing, and schools would no longer think it a part of their duty to promote hatred of possible enemies by means of ignorance hardened by lies.
It can be inferred that schools of today often have to ______.