I was once in an unusual sociology （社会学） class at Brandeis. Each week we studied the  we interacted with one another, and how we  to anger, envy, attention. We were human lab rats. More often, someone  crying. I referred to it as the “touchy-feely”course. Mr. Brown said I should be .     

      One day, Mr.Brown said he had an  for us to try. We were to stand, facing away from our classmates and  backward, relying on another student to  us. Most of us were  with this, and we couldn't let go for more than a few inches  stopping ourselves. We laughed in . 

      Finally, a thin, quiet girl, whom I noticed almost always wear the same clothes, crossed her arms over her chest,  her eyes and leaned back, just like one of those Lipton tea ads  the model dived into the pool. 

      For a moment, I was  she was going to fall on the floor. At the  moment, her parent held her head and  and pulled her up. 

      “Whoa！”several students yelled. Some  . 

      Mr. Brown finally smiled.
      “You see,”he said to the girl, “you closed your eyes. That was the  . Sometimes you cannot believe what you see, you have to believe what you . And if you're ever going to have other people  you, you must feel that you can trust them, ， even where you’re in the dark, even when you're falling.“