求翻译：普通混凝土配合比的设计步骤，首先按照原始资料进行初步计算。得出“理论配合比”；经过试验室试拌调整，提出满足施工和易性要求的“基准配合比”；然后根据基准配合比进行表观密度和强度的调整，确定出满足设计和施工要求的“试验室配合比”；最后根据现场砂石实际含水率，将试验室配合比换算成“生产配合比”。此项工作若采用商品混凝土，则由供货 厂家完成，若采用自拌混凝土，则由施工方委托专业实验室完成。是什么意思？

Mix proportion design of ordinary concrete steps to first preliminary calculations according to the source material. Came "theory combined with than"; after test room try mix adjustment, made meet construction and vulnerable sexual requirements of "benchmark combined with than"; then under benchmark