Paragraph Four
Monday can make us grouchy and depressed, and the feeling is described as the Monday blues. It's probably true that the sound of our alarm clock on Monday morning signals the dawning of a new week and the end of our weekend of fun. Research shows our Monday mood can be based on a direct comparison to the day before. Psychologists call it an emotional shift.
A scientific e() of Monday blues.
【正确答案】：explanation
