美国三次移民 英语版.ppt

文档介绍：The first wave of immigrants in the 17th immigrants were from Western Europe. About 20 percent of the population at this time was African American. The second big wave of immigration happened between 1840 and 1920. During this wave,about 37 million people came to . Let ’s look at the third wave ,the period from 1965 to the present time. During the 1970s and 1980s , about 80 percent of the immigrants were from Latin America and Asia , and only 20 percent were from Europe and elsewhere. Question: Who can tell me the time about three times American immigrantion waves?