Definition
Working diligently and with great effort.
努力工作
Even though it was almost midnight, the students were still hard at it, studying.
虽然已经快到午夜了，学生们仍然在努力地学习。
The team is hard at it, trying to meet the deadline.
团队正在努力地工作，试图在截止日期前完成任务。
She's hard at it practicing the piano every day, hoping to win the competition.
她每天都在努力练习钢琴，希望能赢得比赛。