gōng / rén / xiān / jiǎn / chá / shā / lún / shì / fǒu / ān / zhuāng / láo / gù / rán / hòu / cái / kāi / shǐ / dǎ / mó

工人先检查砂轮是否安装牢固，然后才开始打磨。

The worker first checked that the grinding wheel was securely installed before starting to polish.