阅读短文，选择方框中词的正确形式填空。（每词用一次，有一个为多余）

both,  careful,  study,  help,  always,  return,  rule,  school , cross,  move,  right,

John comes from England. Now he is   in a school in Beijing. When he comes to China, his friends tell him something about some traffic   in China.
People   on the left in England. But in China, people should move on the . Before you cross a street, you must look  ways—look left, look right and look left again.   remember(记住) the traffic moves on the right in China, or you may get hurt. In the morning and the evening, when people go to work and   home, the streets are very busy (繁忙的). So you must be   at this time. When you want to    the road, you must wait(等) for the green “walk” sign. In China, you can always ask the police for  when you lose your way.
John thinks he must obey these rules to keep safe.