tractors拖拉机tractorn.【C】拖拉机；牵引车Tractors full track low speed低速轨道式拖拉机Tractor-trailer combination半挂汽车列车tractor-drawn polydisk plow机引垂直圆盘犁Tractors facilitate farming.拖拉机使耕作便利。Tractor-trailer mobile robot带拖车移动机器人Tractor Noise and its Conditions拖拉机噪声及其控制tractor hydraulic pressure system拖拉机液压系统tractor liquid-hydraulic system拖拉机液压系统Tractor-semitrailer combination半挂汽车列车tractor-drawn plough and harrow机引犁耙