indispensability

This electric drill is a indispensability special equipment at rag trade.

该电锁是服装工业不可缺少的专用设备之一.

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Body and mental state are two aspects of body indispensability, they are mutually to contact interaction.

身体与心理是人体不可缺少的两个方面, 他们是相互联系相互作用的.

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