他们为废除奴隶制而斗争。

They campaigned for the abolition of ___slavery.

从奴隶制的状态，希腊人过渡到一个完全发展和民主的国家的生活。

From the condition of ___slavery, the Greeks passed to life in a fully developed and democratic country.

美国的奴隶制历史是一个复杂而痛苦的话题。

The history of ___slavery in the United States is a complex and painful topic.