Zìcóng chū le shì, tā jīn fēi xī bǐ, zhěnggè rén dōu biàn le.
Since the incident, he has changed completely — he's not the same person he was.
Tips
usage
今非昔比 can be used positively (impressive improvement) or neutrally/negatively (unrecognizable change). Context determines the tone. The literal meaning is: 'today (今) is not (非) like the past (昔), [there is no] comparison (比).'
