2. The document reading apparatus according to claim 1 , wherein the topic relation presenting device presents the description parts taken out side by side.
2. The document reading apparatus according to claim 1 , wherein the topic relation presenting device presents the description parts taken out side by side. 3. The document reading apparatus according to claim 2 , wherein the topic relation presenting device presents the related parts and original documents in two windows, one of the windows including the related parts side by side and the other including the original documents side by side.