Tonight is used to refer to the evening of today or the night that follows today.
I'm at home tonight.
我今晚在家。
Tonight he proved what a great player he was.
今晚他证明了自己是一个多么了不起的选手。
Tonight is used to refer to the evening of today or the night that follows today.
Tonight is the opening night of the opera.
今晚是这部歌剧的首演之夜。