When was the last time you flashed a fake smile at the office For some, it may be just another mundane (乏味的) aspect of work life—putting on a game face to hide your inner unhappiness. But new research suggests that it may have unexpected (36) : worsening your own mood and (37) you to withdraw from the tasks at hand. In a study, scientists tracked a group of bus drivers for two weeks, focusing on them because their jobs require (38) , and generally courteous, interactions with many people. The scientists examined what happened when the drivers (39) in fake smiling, known as "surface acting", and its opposite, "deep acting", where they generated (40) smiles through positive thoughts, said an author of the study, Brent Scott, an assistant professor of management at Michigan State University. After following the drivers closely, the researchers found that when the smiles were forced, the subjects’ moods deteriorated and they (41) to withdraw from work. The fact of trying to (42) negative thoughts, it turns out, may have made those thoughts even more (43) . But when the subjects tried to (44) smiles through deeper efforts—by actually cultivating pleasant thoughts and memories—their overall moods improved and their productivity increased. Women were affected more than men. Dr. Scott suspected cultural norms might be at play: women are more (45) expressive in social intercourse, he said, so hiding emotions may create more strain. Research suggests that an inauthentic smile to hide unhappiness can further worsen your mood. A．attractions B．authentic C．causing D．completely E．consequences F．contribution G．display H．emotionally I．engaged J．frequent K．persistent L．retreat M．stable N．suppress O．tended