From the third paragraph, we can know ______.
A．few immigrant groups try to maintain their own cultural tradition, language, and religious practices
B．some groups, such as the Huguenots French Protestants) who immigrated during the colonial period, did not assimilate within one or two generations
C．others, such as the German and Irish immigrants of the 19th century, still maintain some characteristics of their traditional cultures
D．all the immigrants have absorbed in the beliefs and standards of the dominant society