他几次偷偷地回到美国帮助其他奴隶通过地下铁路获得自由。的翻译：He sneaked back to the United States helped free the other slaves through the underground railway. 什么意思？中文翻译英文，英文翻译中文，怎么说？

青云英语翻译

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He sneaked back to the United States helped free the other slaves through the underground railway.

He several times returns to US to help other slaves secretly to obtain the freedom through the underground railway.

He has on several occasions she secretly came to the United States helped other slaves to freedom through underground railway.

He sneaked back to the United States helped free the other slaves through the underground railway.