Adding proper amount of crystal sugar and lemon slices can reduce the generation of tea scale.

There seems to be some misleading words in this question. First of all, "making tea with the earth" is unreasonable. We can't make tea with the earth, because the earth is a planet, not a creature or an object. Secondly, the question of "what can be added to reduce tea scale" is also wrong, because tea scale is usually caused by substances in tea at high temperature, not by additives.

However, according to the hint of "lemon slices with rock sugar" in the question, I guess you may be asking how to make lemon slices with rock sugar. Rock sugar and lemon slices can be used to make tea together, and this combination can reduce the generation of tea scale.

Citric acid in lemon slices can react with substances in tea, thus reducing tea scale in tea. Therefore, according to this hint, the answer should be: adding a proper amount of rock sugar and lemon slices when making tea can reduce the generation of tea scale.

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