extemporize
vt. 即兴创作,即席演奏
If you extemporize, you speak, act, or perform something immediately, without rehearsing or preparing it beforehand.
He completely departed from the text and extemporized in a very energetic fashion.
他完全脱稿,慷慨激昂地进行即席演说。
1. manage in a makeshift way; do with whatever is at hand;
2. perform without preparation;
He had to extemporize because he had forgotten to bring his notes.
他因为忘了带讲稿,只好即席发言.