英語三級每日口語(7.20)：Its origin is still a mystery now

Its origin is still a mystery now.
    它的起源至今仍是個(gè)謎。
    今天的幾個(gè)句子是有關(guān)起源的：
    1.Speculate on the origin of the universe.
    探究宇宙的起源。
    2.The origin of Ruby Fall.
    紅寶石瀑布的起源。
    3.To investigate the origin of the misfortune.
    追究禍源。