APhoneThatKnowsYou’reBusy
It’samodernproblem：you’retoobusytobedisturbedbyincessant(连续不断的)phonecallssoyouturnyourcellphoneoff.Butifyoudon’tremembertoturnitbackonwhenyou’relessbusy.youcouldmisssomeimportantcallsifonlythephoneknewwhenitwaswisetointerruptyou，youwouldn’thavetoturnitoffatall.Instead，itcouldletcallsthroughwhenyouarenottoobusy