假定英语课上老师要求同桌中间交换修改作文，请你修改你同桌写的以下作文。文中共有10处错误，每句中最多有两处，每处错误仅涉及一个单词的增加、删除或修改。
增加：在缺词处加个漏字符号（），并在其下面写出该加的词。
删除：把多余的词用斜线（\）划掉。
修改：在错的词下划一横线，并在该词下面写出修改后的词。
注意：1）每处错误及其修改均仅限一词；
2）只允许修改10处，多者（从第11处起）不计分。
China is an ancient civilization with culture dated back more than 4,000 year. Basic elements for a modern world such as paper, gunpowder, or the magnetic compass originated in China.
Today, China is again at the forefront of the world, with Chinese goods reaching all parts of the world. The Chinese culture have also fascinated many people. In the Shaolin Monasteries or the Forbidden City of Beijing, China has its unique art and architecture that what draw thousands of visitors every year. The Chinese food is equal popular around the world and it is loved by many non-Chinese. In China, the food can be found in great varieties and was different region to region. So join we and experience all these.
，那么正方体的棱长等于 （ ）