on principle   (TTS發音)

as a moral matter按道理；原則上

    He drinks a cup of hot milk every night on principle. 他每晚照例喝一杯熱牛奶。

    I dislike going out for meals in restaurants on principle； why should you pay so much money for food that you could prepare yourself？我就是不喜歡去外面餐館吃飯，幹嗎要花那麼多錢去買那些自己能做的食物呢？