布克曼主义者的

We've all learned about the courageous acts of former slaves in American history like Frederick Douglass and Harriet Tubman—but while the Emancipation Proclamation of 1863 officially put an end to slavery in the United States, human trafficking is still at critical mass and rising in many parts of the world, with more than 27 million people enslaved today.

我们对于美国前奴隶及废奴主义者弗雷德里克·道格拉斯，海丽特·塔布曼的英雄事迹早已耳熟能详——但尽管1863年制定的《解放黑奴宣言》官方上终止了美国的奴隶制，却没能从根本上阻止全世界各地贩卖人口的恶潮，直到今天，仍有超过两千七百万的人遭奴役。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。