The source of infection was undetermined.

感染源尚未确定。

The cause of the plane crash was undetermined.

飞机失事原因尚未查明。

The cause of his illness and death remain undetermined.

他的疾病和死亡原因仍未确定。

Undetermined if there will be experience loss for this.

是否会有经验的损失还没确定。

The cause of his illness and death remained undetermined.

他的疾病和死亡原因仍未确定。