为什么它失去以前我们从不知道我们曾拥有它的英文

why do we never know what we've got till it's gone

• 为什么:    why; why is it tha ...
• 它:    it
• 失去:    lose
• 以前:    before; formerly; ...
• 我们:    we
• 知道:    know; realize; be ...
• 曾:    relationship betwe ...
• 拥有:    possess; have; own