这次飞机坠毁被归因于机械故障。

The plane crash was attributed to a ___mechanical failure.

汽车因机械故障抛锚，让我们困了好几个小时。

The car broke down due to a ___mechanical defect, leaving us stranded for hours.

我的兄弟是一名设计工业机械的机械工程师。

My brother is a ___mechanical engineer who designs industrial machinery.