BBC在线收听下载:美国称知道朝鲜是索尼影业黑客袭击幕后黑手

1.Now leaked documents and testimonies from former officials are found to answer public domain, appearing to back up Washington's case.

back up 支持，证实，援助；（资料）备份；倒退；裱

Radio signals received from the galaxy's centre back up the black hole theory.
从该星系中心接收到的无线电信号证实了黑洞理论。

Make a point of backing up your files at regular intervals.
要特别注意定期备份你的文档。

2.The researches say that they don't fully understand the mechanism but tracking down the parasites with the genetic variation could help them to identify the area where resistance may spread next.

track down 追捕

She had spent years trying to track down her parents.
她已经花了多年试图找到她的父母。

They have tracked down the spy.
他们已经追捕到那个间谍。