pick at
1．eat without appetite挑食
Stop picking at your food， Janet！
Eat it all up or you won't have any pudding！珍妮，不要挑食！全部吃下去，否则就不给你吃布丁了！
She had no appetite and only picked at food．她食欲不振，只吃了一点点食物。
2．find fault with对…吹毛求疵
They showed their displeasure by continually picking at her．他们不断挑她的毛病以示他们的不满。
She'd been picked at so often by parents and teachers that she didn't know how to behave．家长和老师经常对她吹毛求疵，她简直不知怎么办才好。