这些拖拉机是农场的得力干将，每天都能完成繁重的耕作任务。

The tractors are the farm's reliable ___workhorses, handling heavy plowing tasks every day.

这些卡车是我们物流系统的中坚力量，每天都能准时完成运输任务。

These trucks are the ___workhorses of our logistics system, delivering goods on time every day.