他说是疲劳导致了那个错误。

He said it was ___tiredness that caused the error.

我突然被一阵疲倦感袭来。

I was overtaken by a sudden wave of ___tiredness.

我感到如此放松，我的疲倦几乎完全消失了。

I felt so relaxed and my ___tiredness disappeared almost entirely.