Because of Delaware’s lenient laws regarding business incorporation, many companies have their headquarters in the state’s largest city, Wilmington.

单项选择题Because of harsh weather conditions, more than a dozen states in the United States were declared disaster areas in 1977.

单项选择题To cool itself, a rhinoceros soaks in mud or water because its thick hide has no sweat glands.

单项选择题In the eighteenth century the heading of “natural philosophy” encompassed all of the sciences.

单项选择题Leaves are not distributed accidentally on a plant stem, but are arranged in a very precise way that assures them the maximum light.

单项选择题The members of Aaron Burr’s family were noted for their passionate and headstrong temperament.