If the machinery were not maintained properly, It would get rusty as time passes.

机器要不好好养护，久而久之就要生锈。

《新英汉大辞典》

High reliable power supply module parallel connection system will not achieve (even lower) the reliability level that it should have if it is not designed and maintained properly.

电源模块并联馈电是高可靠系统，设计或维修使用不当，不但不能发挥其高可靠性水平，而且还会进一步降低系统可靠性。

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Because it has the ability to absorb foreign materials, it will yellow over time if it is not properly maintained.

因为它有吸收外界物质的能力，如果不妥善保管的话就会泛黄。

youdao

Most late model cars, after all, are designed to run for at least 200, 000 miles if properly maintained.

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If properly maintained its value will generally increase.

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The government should recognize that greed exists and control it, just as the government recognizes that airplanes will fall from the skies if planes are not properly maintained and operated by skilled professionals.

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