To accumulate over a long period of time; to gather steadily day by day and month by month; to build up gradually.
坚持锻炼身体，日累月积，健康状况会越来越好
By persisting in daily exercise, your health will improve remarkably through gradual accumulation.
Next Idiom
To accumulate over a long period of time; to gather steadily day by day and month by month; to build up gradually.