75. Sometimes the police use 　　　　　trained dogs to catch thieves.

74. English can help　　　　　 know more about the world.

73. I'm going to be a　　　　　 　when I grow up, because I want to live in the countryside.

72. The two pictures look same, so I'm 　　　　　　to see the difference.

A)根据句意，从方框中选出恰当的单词，用其正确形式填空。每空格限填一词，每词限用一次。

71. I think documentaries are 　　　　　　　because I can learn a lot from them.