labor which is exchanged with capital

例句：

1. 1. The workers are hard at work on the construction site.
   工人们正在工地上辛勤工作。
2. 2. He labored all night to finish the project.
   他通宵达旦地完成了这个项目。
3. 3. The farmers are busy with their labor every day.
   农民们每天都在忙碌着他们的劳动。