完形填空。      It was a cold winter afternoo

     It was a cold winter afternoon. Robert stopped for a moment as he crossed the bridge and looked
down at the river below. There were hardly any    1    on the river. Near the bridge, however, almost
direct below,    2    was a small canoe (独木舟), with a boy in it. The boy was wearing   3    and shivering (颤抖) with cold, Robert noticed.     
     Just then he heard a cry, “Help! Help!” The cry    4    from the river. Robert looked down. The boy
was    5    the water and his canoe was floating away. “Help! Help!” he called again.    
      Robert was a good    6    . Taking off his clothes, he    7    into the river.
The    8    water made him tremble（颤抖） all over,     9    in a few seconds he reached the boy. 
“Don’t be afraid,” he said and started to swim towards the river bank,  10    the boy with him. But at
that    11   he noticed a large motor boat under the bridge. There were several people on the boat,
all    12   in his direction. Robert    13   to swim towards the boat.   
     “Give me a hand,” he shouted    14   he got near the boat. He    15   up into a row of faces. “It’s
funny,” he thought. “They look so    16    .” Silently they helped the boy into the
boat and    17   him in a blanket (毯子). But they did not move to    18   Robert.  
      “Aren’t you going to pull me    19   , too?”  
    “You!” said one of the men. Robert noticed that he was standing next to a large    20   . “You! Why,
we were making a film and you spoiled (破坏) a whole afternoon’s work! You can stay in the water!”