单项选择题

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, 1 , depends first and 2 on its capacity to produce wealth. "Wealth" in this sense is not money, for we do not live on money, 3 on things that money can buy: "goods" such as food and clothing and "services" such as transport and 4 .
A country"s capacity to produce wealth depends upon many factors, most of 5 have an effect on one another. Wealth depends 6 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 7 with coal and minerals, and have a fertile soil and a 8 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 9 her borders, her soil is fertile, and her climate is 10 The Sahara Desert, on the other hand, is one of the least wealthy.
Next to natural resources 11 the ability to turn them to use. China is perhaps as well 12 as the U.S.A. in natural resources, but suffered for many years from civil and 13 wars, and for this and other reasons was unable to develop her resources. 14 and stable political conditions, and 15 from foreign invasion, enable a country to develop her resources peacefully and steadily, and to produce more wealth than another country equally well 16 by nature but less well ordered. Another important factor is the technical 17 of a country"s people. Old countries that have, through many centuries, trained up numerous skilled craftsmen and technicians 18 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 19 for saving, and can put their savings into factories and machines which will help workers to 20 more goods in their working day.

A.effectiveness
B.efficiency
C.sufficiency
D.affection