載入中... 相關課程 Back EP1:尋聲 登入觀看 ⇐ Use this menu to view and help create subtitles for this video in many different languages. You'll probably want to hide YouTube's captions if using these subtitles. EP1:尋聲 : 此影片內容包含:回聲、聲波反射 上傳學習單 下載學習單