Array ( [0] => Array ( [title] => L17A [link] => https://www.youtube.com/embed/DswHc-vnAL4 ) [1] => Array ( [title] => L17B [link] => https://www.youtube.com/embed/L9NGdcBrX9I ) [2] => Array ( [title] => L17C [link] => https://www.youtube.com/embed/OoaIIgc3JPM ) ) 國立清華大學開放式課程OpenCourseWare(NTHU, OCW) - 第17R講 Orientation of a Surface