[单项选择]The United States of America, with a population of 255.5 million in 1992, was the ______ most populous country in the world.
A. second
B. third
C. fourth
D. fifth

[单项选择]While the population of the United States includes a great variety of racial and ethnic backgrounds, Japan's population is______.
A. autonomous
B. homogeneous
C. ambitious
D. anonymous

[单项选择]What's the population of the United States according to the passage


A. 7,000,000.
B. 14,000,000.
C. Twice of the young persons under twenty-five.
D. Not mentioned.

[单项选择]

The population of the United States is only 6% of the world’s population, but Americans (21) one third of all the energy (22) in the world. This fact alone says that Americans need to use less energy. And because the price of energy had been rising very rapidly (23) the limited supplies of oil in particular, Americans are becoming aware to the need to (24) energy. In California we have a California Energy Commission which has set up in the past five years to (25) plan for our future energy use. We have (26) laws in California to help us conserve energy. First of all, our houses in California have been very (27) of energy in the past. They were not (28) very carefully and so the heat would go out of the house very rapidly. Now we require that the homes have a (29) level of insulation, and so the homes built now are much more (30) .
(31) , in transportation (32) a
A. fashionable
B. luxurious
C. efficient
D. effective