A concept is a form of thinking that reflects the essential attributes of an object. The extension of a concept refers to all objects that have the essential attributes reflected by the concept. According to whether there is an overlapping part between concept extensions, the relationship between concepts can be divided into compatible relations and Incompatible relationship: The compatible relationship between concepts refers to the relationship where the extensions of two concepts at least partially overlap. According to the above definition, Which of the following concepts are not compatible:. ['Conductor-semiconductor.', 'U. S. Capital-Washington.', 'Writer-Chinese Writer.', 'College students-Communist Party members.']