她认为彼得去世是医生的错。

She believes it was the ___doctor's ___fault that Peter died.

她没来不是我的错！

It's not ___my ___fault she didn't come!

“是我的错，”我说，他回答道，“没关系，一切都好。”

"It's ___my ___fault," I said, and he answered, "Never mind, it's all ok."