阅读判断。根据短文内容，判断下列句子的正与误。

Long long ago, there was no paper in the world. People had to write characters(汉字) in bamboo slips or stones.Then there was a man named Cai Lun who was a Chinese man. He made people use all kinds of things to invent paper. From then on, people can use paper to write on. Paper is a great invention. We always remember the great inventor Cai Lun. Nowadays paper is very useful in our work, study and our life.It really means a lot to human beings

在右图的正方体中，M、N分别为棱BC和棱CC₁的中点，则异面直线AC和MN所成的角为(   )

一四____     二____得六       三五____

____五一十     三____得九      四四____

____四得八     五____二十五     五六____