Grace was going to have a test. She studied hard, but she was still worried, because she was not good at math. “Wow!” said Adam. “You walked under a ladder( 梯子 )!” Grace looked at Adam and asked, “So what?” “It’s Friday the 13 th . That’s bad luck already and you just made it worse by walking under a ladder.” Bad luck? Grace didn’t need bad luck before her test. “Do you really believe those things?” asked Grace. “There must be a reason why so many people are superstitious( 迷信的 ) about them, right?” said Adam. Grace walked into the classroom and sat in her seat. She thought she couldn’t do well in the test because of the bad luck. The test began. Grace read through the problems, and to her surprise, they didn’t look too hard. She worked out each problem carefully. When she finished, she brought her paper up to Mr. Saunders’ desk. Mr Saunders started to grade it. Grace went back to her seat and was still worried about her bad luck. “Grace, could you come here?” asked Mr Saunders. Grace walked up to Mr Saunders’ desk. She expected to see a lot of red marks on her paper. But she saw a big A. “I got an A?” “Yes,” said Mr Saunders. “I’m very glad with your improvement.” Grace was happy for the rest of the day and when a black cat walked in front of her on the way home from the bus stop, she just smiled. Friday the 13 th wasn’t bad luck for her.