やり出す

やりだす【やり出す】

begin [start] 《to do, doing》; set about [commence] doing; set about 《one's task》; embark on…; take up; 〔急に〕 jump into 《an action》.

●母は 50 過ぎてから水泳をやりだした. My mother took up swimming after she was 50.

・あの男は次に何をやりだすかわかったものではない. You never know what he'll do next.

・やりだすと止まらない. Once I get started, there's no stopping me.