He completely departed from the text and extemporized in a very energetic fashion.
他完全脱了稿并以一种精力非常充沛的样子即席演说。
vi. 即兴演奏或演说;临时凑合
improvise
adj. extemporaneous、 extemporary、 extempore
adv. extemporaneously、 extempore