1. unknown quantity
   未知量，未知数
   
2. unknown soldier
   n. 阵亡的无名英雄,无名战士
   

1. We use x as the symbol for an unknown quantity.
   我们用ｘ表示一个未知数。
2. We bought a drawing by an unknown artist.
   我们买了一幅某个不出名的画家所作的画。
3. The poet's burial place remains unknown.
   那位诗人的葬身之处仍然不清楚
4. He was a man quite unknown about town.
   他在镇上鲜为人知。
5. The outcome of their discussion is still unknown.
   他们讨论的结果仍然不清楚。

　3个名词解释

　5个形容词解释