The investigation is still underway.

调查仍在进行中。

youdao

Investigation into the accident is still underway.

事故原因的调查正在进行当中。

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"Investigation of the crash is still underway, and the cause of the crash has not been determined," the agency said.

“飞机坠毁事件的调查仍在进行中，飞机坠毁的原因还没有确定，”该机构说。

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But as I say, this investigation by the FBI is still underway.

BBC: News | BREAKFAST WITH FROST | Defence Secretary Geoff Hoon