Mẫu trò chơi Đồng hồ cát trên PowerPoint

 STARTTIME’S TIMER UP! TIME LIMIT: 
 30 seconds STARTTIME’S TIMER UP! TIME LIMIT: 
 2 minutes STARTTIME’S TIMER UP! TIME LIMIT: 
 10 minutes STARTTIME’S TIMER UP! TIME LIMIT: 
 30 minutes