Compare and contrast
By understanding similarities and differences between two things, we can increase our understanding and learn more about both. This usually involves a process of analysis, in which we compare the specific parts as well as the whole. Comparison may also be a preliminary stage of evaluation. For example, by comparing specific aspects of A and B, we can decide which is more useful or valuable. Many paragraphs whose function is to compare or contrast will begin with an introductory sentence expressed in general terms.