gōng / zuò / rén / yuán / yòng / qīng / shuǐ / jiān / xǐ / qì / jù / zhǔn / bèi / kāi / shǐ / shí / yàn

工作人员用清水湔洗器具，准备开始实验。

The staff washed the equipment with clean water before starting the experiment.