已知x²-6x+ k²是一个完全式，则k的值是（ ）

   Mr. George works at the school lost and found. He works very carefully. Every day, when he gets a lost thing, he takes notes about it. There are pens, books, school uniforms, keys, walkmans and many other things in the lost and found. Most of them are the students’. If you lose your things, it’s easy for you to go to the lost and found for help. But you must tell Mr. George what it is and its color and the day when you can’t find it. I think Mr. George is very helpful, and you will be happy when you find the lost there.

这个故事,与"夸父逐日"一样,具有浓重的悲剧色彩,但两个故事中人物的共同精神是什么

下列句子中没有语病的一项（     ）