其关键部件在接近使用寿命极限时，产品质量极不稳定。

When its key parts close to their life time, products quality is very unstable.

youdao

其关键部件在接近使用寿命极限时，产品质量极不稳定。

When its key parts close to their life time, products quality is very unstable.

youdao