dirtn.污垢；泥土；灰尘dirt screen尘土分离筛dirt tester杂质测定器dirt course砂土跑道dirt bailer泥浆泵dirt shroud防尘罩dirt-sliden.土滑道dirt-proof防尘的dirt content尘埃含量dirt-cheapadj.毫无价值的；贱如粪土的adv.非常便宜地dirt-trackn.跑道；赛车跑道；泥铺跑道