Thousands of years before Columbus came to the New World, the American Indians entered Nor

th America by crossing a narrow strip of land that once connected Alaska and Siberia. The migrants entered a new world in which there were no people at all. But there were many animals to hunt, and there were forests where nuts, roots and berries could be gathered.

(27) When the Europeans came to the New World, the Indians, at first, taught the settlers how to plant corn, bake fish, make canoes and smoke tobacco. In return, the whites introduced horses, guns, gun-powder and alcohol. But at last, there were struggles for land, and the struggles could have only one result-war. When the wars were over, all Indians were moved to large tracts of land called reservations. Now, some of them, embittered by past mistreatment, are determined to preserve their tribal life; some wish to modernize the reservations. These alternatives, with many variations, are what most Indians have chosen-a future in modern technology and education, or the revival of ancient tradition and treaties.

The Indians entered North America______.

A．with Columbus

B．before Columbus did

C．after Columbus' arrival

D．in the 18th century