单选题 .  The "standard of living" of any country means the average person's share of the goods and services which the country produces. A country's standard of living,     21    , depends first and     22    on its capacity to produce wealth. "Wealth" in this sense is not money, for we do not live on money,     23    on things that money can buy: "goods" such as food and clothing and "services" such as transport and     24    .
    A country's capacity to produce wealth depends upon many factors, most of     25    have an effect on one another. Wealth depends     26    a great extent upon a country's natural resources, such as coal, gold, and other minerals, water supply and so on. Some regions of the world are well     27    with coal and minerals, and have a fertile soil and a     28    climate; other regions possess perhaps only one of these things, and some regions possess none of them. The U.S.A. is one of the wealthiest regions of the world because she has vast natural resources     29    her borders, her soil is fertile, and her climate is     30    . The Sahara Desert, on the other hand, is one of the least wealthy.
    Next to natural resources     31    the ability to turn them to use. China is perhaps as well     32    as the U.S.A. in natural resources, but suffered for many years from civil and     33    wars, and for this and other reasons was unable to develop her resources.     34    and stable political conditions, and     35    from foreign invasion, enable a country to develop her resources peacefully and steadily, and to produce more wealth than another country equally well     36    by nature but less well ordered. Another important factor is the technical     37    of a country's people. Old countries that have, through many centuries, trained up numerous skilled craftsmen and technicians     38    better placed to produce wealth than countries whose workers are largely unskilled. Wealth also produces wealth. As a country becomes wealthier, its people have a large     39    for saving, and can put their savings into factories and machines which will help workers to     40    more goods in their working day.21.