shí / yàn / rén / yuán / xiān / jiā / rù / zhōng / hé / jì / zài / màn / màn / tiáo / jié / róng / yè / de / suān / jiǎn / dù

实验人员先加入中和剂，再慢慢调节溶液的酸碱度。

The lab technicians first added a neutralizing agent and then slowly adjusted the solution's pH.