speak impromptu; make an impromptu speech; off-the-cuff remarks
Related Translations:
即席: [书面语]1.(当座; 当场) impromptu; extemporaneous; extempore; off the cuff; offhand 短语和例子即席发言 make an extemporaneous speech; give an offhand talk; give a talk offhand; 即席讲话 off-the-cuff remarks; 即