“underground railroad”簡單造句，underground railroad造句子

In 2004 a center in honor of the 'underground railroad' opens in Cincinnati.

Harriet Tubman, another great woman, led hundreds of American slaves to free-dom along the underground railroad, risking her life over and over again to bring her fellow slaves to freedom.

Negro slaves took great chances to escape to freedom. Many gained their freedom through the so-called "underground railroad."