Her impromptu speech was well-received, giving her new confidence in her ability to speak off the cuff.

　　【考法1】n. 即席的表演： something, such as a speech, that is made or done extemporaneously

　　【近】 improvisation, extemporization

　　【考法2】adj. 即席的，即兴的：composedwithout previous preparation.

　　【例】 Our dinner guest thanked us with an impromptu song. 客人们即兴高歌一首以表达谢意

　　【近】 ad-lib, extemporary, improvised, offhand, unplanned, unpremeditated, unprepared, unrehearsed

　　【反】 considered, planned, premeditated, prepared, rehearsed 事先有所准备的