These aids would have been indispensable to very early people who would have found the process impossible without some form of mechanical aid.

远古人类会发现在缺少某种形式的机械辅助的情况下，这一过程是不可能实现的，这些辅助对他们来说不可或缺。

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These aids would have been indispensable to very early people who would have found the process impossible without some form of mechanical aid.

远古人类会发现在缺少某种形式的机械辅助的情况下，这一过程是不可能实现的，这些辅助对他们来说不可或缺。

youdao