Definition: used in particular phrases to mean 'gradually' or 'in units of' Level: B2
他一天天变得更强壮。
___Day ___by ___day he grew stronger.
天气一天天变得越来越暖和，没有人想念冬天的雨和严寒。
The weather gets warmer and warmer ___day ___by ___day, and no one misses the rain and severe cold of winter.
她一点一点地存钱买一辆新自行车。
She saved money ___little ___by ___little to buy a new bicycle.
