The immediate cause of death is unknown.

造成死亡的直接原因不明。

《牛津词典》

The cause of her death is still unknown.

关于其死亡的原因至今还未知晓。

youdao

They were never autopsied, and the cause of death remained unknown.

但是并没有进行验尸，死因不明。

youdao

They were never autopsied, and the cause of death remained unknown.

但是并没有进行验尸，死因不明。

youdao