A、Planting crops. B、Building houses. C、Clearing new land. D、Caring for animals. D事实细节题 文中提到拓荒者们由于忙于建造房屋、开垦荒地和种植谷物，没有时间来照看家畜。

The animals you would have seen on a typical farm in Massachusetts in the early 1800s would not look quite the same as the ones you might see in the 1980s. In colonial times settlers brought cattle and sheep with them to America from various parts of Europe. Because the settlers were busy building houses, clearing land and planting crops, they had little time to care for their animals. The cattle and sheep had to fend for themselves and females were bred to whatever bulls or rams in the neighborhood. These matings resulted in mixed breeds of cattle and sheep that can hardly survive under adverse conditions. As the herds grew, they provided the settlers with meat as well as milk and wool. That was almost all the 19th- century farm families needed, enough food for themselves and a little surplus that could be traded for things they couldn’t produce at home. Now the survival of farm animals is not so precarious. Breeding is much more selective and specialized, pure-bred cattle and sheep predominate, some bred for their meat, others for their milk or wool.