A．workers in factoriesB．cotton pickersC．migrantsD．slave……

单项选择题In English all the prefixes are ______ morphemes.

单项选择题After the American Revolution, ______ became the first capital of the United States, being already the largest city in North America.

单项选择题The novel ______ by Samuel Richardson is considered the first English psycho-analytical novel.

单项选择题In general, children's holophrastic sentences begin ______.

单项选择题The first settlement in Australia was made by the ______.