runsthin
—phrasal verbwithrunverbuk/rʌn/us/rʌn/present participlerunning|past tenseran|past participlerun
UK(USbreaksthin)If yourunin avehicle, you use itcarefullyandslowlyfor ashorttimewhen it is new, so that you do notdamageitsengine.
（小心缓慢地）试开（新车），使（新车发动机）试转