C. then adding the main materials after the bottom materials react steadily;

当底料反应平稳后，再加入主料；

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B firstly adding the bottom materials for smelting at the initial stage of smelting;

冶炼初期，首先加入底料进行冶炼；

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Pour the materials onto the base and use the rubber scratch board to make the surface flat and make the bottom materials permeate into the cement base. Do not leave some areas unpainted.

将物料倒于基面，用橡胶刮板刮平，要求不得漏涂，使底料渗透于水泥基层中。

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Knowledge sharing led to extremely successful business opportunities for companies like GE and construction company Cemex (in green energy and building materials directed toward the bottom of the period in Latin America, respectively).

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Many companies want to use alternative materials and design, but the bottom line is cost.

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The bottom line is that the researchers can produce high-precision materials using the same methods that plastics are produced.

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