unprecedented

US /ʌnˈprɛsɪˌdɛntɪd/

UK /ʌnˈpresɪdentɪd/

B1 中級英檢高級
adj.形容詞空前的 ; 前所未有的
The election of an inexperienced president was unprecedented in our history

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太陽能如何變得如此便宜 (How solar energy got so cheap)

06:31太陽能如何變得如此便宜 (How solar energy got so cheap)