题目

The United States covers a large part of the North American continent. Its neighbors are Canada to the north and Mexico to the south. Although the United States is a big country, it is not the largest in the world. In 1964, its population was over 185,000,000.    When this land first became a nation, after winning its independence (独立) from England, it had thirteen states. Each of the states was represented(代表) on the American flag by a star. All these states were in the eastern part of the continent. As the nation grew toward the west, new states were added and new stars appeared on关于俄罗斯工业叙说正确的是（ ）A. 以农业为主 B. 航天航空工业发达C. 工业分布均匀 D. 轻重工业都发达