tiān qì / zhuǎn liáng / hòu / gōng zuò rén yuán / wèi / wēn shì / jiā wēn / fáng zhǐ / yòu miáo / shòu dòng天气转凉后,工作人员为温室加温,防止幼苗受冻。After the weather turns cooler, the staff heat the greenhouse to keep the seedlings from freezing.