1、Bill was a very good pilot（飞行员）.He had been in the air force for several years, and had been very successful. Now he was sent to a small field in the middle of a forest,  36  planes were able to attack the enemy very easily,  37  it was near the front line, but  38  to find. The forest tress were very tall and very  39  on all sides, so planes had to go down very quickly and then stop their falling very  40  before they  41  on the ground. Only the  42  pilots were able to land safely, and even some of those lost their planes and  43  because they hit the trees on the ground.

After Bill had arrived, he was not  44  until he was able to fly closer to the trees than any of  45  pilots, and soon all the pilots who used that field were trying to  46  each other at flying  47  over forest. Every time one of their planes came back from the attack on the enemy, the other pilots used to run  48  and watch, to see how near the trees  49  pilot took it, if the succeeded in taking very near, they laughed and shouted.

Bill soon  50  exactly how near he was able to go safely, and then one day he flew so close to the  51  of the trees that some of the branches  52  the bottom of his plane. The other men in the plane seemed rather  53 , but Bill only laughed as he landed the plane without any  54  in the middle of the field  55  the other pilots on the ground shouted happily. ”How silly I am!” he said. ”I forgot that the trees had grown since yesterday!”