impromptu
adj, adv (done) without preparation, rehearsal or thought in advance 事先無準備(的); 臨時(的); 即興(的); 即席(的)
an impromptu speech, news conference, performance,etc 即席講話、 臨時召開的記者招待會、 即興表演
He spoke impromptu. 他臨時發了言. impromptu, n musical composition, etc that is or appears to be improvised 即興曲
an impromptu by Schubert 舒伯特的即興曲.