the company someone keeps idiom
…所交往的人，与…为伍的人
the influence of the people that someone spends time with
"Where does he pick up words like that?" "It's the company he keeps." “他从哪儿学的那种话？”“从他结交的朋友那里。”
He's been keeping bad company (= spending time with unsuitable people). 他交了一些不三不四的朋友。