Population, race and ethnic groups 人口和种族
①the third most populous country in the world,with 255.5 million people.
②a nation of immigrants.Immigration accounts for a major source of population growth.There are many racial and ethnic groups. Between 80% and 90% of immigration ot the United States now is from Asian and Hispanic counties.The first immigrants in American history came from England and Netherlands. Population movements are common in America.移
2)Black people and the Civil Rights Movement 黑人和民权运动
①blacks and slavery
the largest of the racial and ethnic minorities in the U.S., which 12.1 per cent of the population; the first blacks were brought to North America as slaves in 1619. 美国最大的少数人种是黑人，占人口的12。1%；1619年最早的人人作为奴隶被运至美国。
②The slave system was formally ended by Lincoln's Emancipation Proclamation in 1863 and the Thirteenth Amendment to the Consititution in 1865.the Civil Rights Movement in the 1960s demanded desegregation and equal right.1863年林肯总统的《解放宣言》和1865年的《宪法第13修正案》使奴隶制度正式瓦解。废除种族隔离和人权平等导致了1960年的民权运动。