During the conference, the scientist gave an impromptu demonstration of the new microscope's capabilities using a leaf sample.
会议期间，科学家用一片叶子样本即兴演示了新显微镜的功能。
Which choice best defines “impromptu”?
C — Done without preparation; improvised.. “impromptu” means Done without preparation; improvised..
Which word means “Done without preparation; improvised.”?
B — impromptu. “impromptu” means Done without preparation; improvised..
impromptu — Done without preparation; improvised.. In Chinese: 即兴的;临时的.
impromptu is pronounced //ɪmˈprɒmptjuː//.
During the conference, the scientist gave an impromptu demonstration of the new microscope's capabilities using a leaf sample. (会议期间，科学家用一片叶子样本即兴演示了新显微镜的功能。)
unrehearsed, extemporaneous, spontaneous — all close in meaning to impromptu (Done without preparation; improvised.).
planned, prepared — each the opposite of impromptu (Done without preparation; improvised.).
Yes. impromptu is on the SAT Prep Difficult list — the higher-register words that decide the hard questions. The Digital SAT does not test vocabulary in isolation; words like this one are tested through Words in Context questions, where you choose the word that completes a passage most logically and precisely.
in promptu(现成) → 临场发挥。