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  _____    __   __    ______    _____     ______  
 /  ___||  \ \\/ //  /_____//  |  ___||  /_   _// 
| // __     \ ` //   `____ `   | ||__      | ||   
| \\_\ ||    | ||    /___//    | ||__     _| ||   
 \____//     |_||    `__ `     |_____||  /__//    
  `---`      `-`'    /_//      `-----`   `--`     
                     `-`

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發送短信 : Exploring students conceptual understanding of forces