为什么在数学教学中要贯彻理论与实际相结合的原则？

     I know I should have told the headmaster at the time. That was my real     1   .
     He had gone out of the study for some    2   , leaving me alone. In his absence I looked to see
what was on his desk. In the     3     was a small piece of paper on which were written the     4    
"English Writing Prize 1949. History Is a Series of Biographies ".
     A(n)     5     boy would have avoided looking at the title as soon as he saw the   6   . I did not.
The subject of the English Writing Prize was kept a    7   until the start of the exam, so I could not
   8   reading it.
When the headmaster     9    , I was looking out of the window.
     I should have told him what had     10     then. It would have been so     11     to say: "I'm sorry,
but I     12   the title for the English Writing Prize on your desk. You'll have to    13     it."
     The chance passed and I did not    14   it. I sat the exam the next day and I won. I didn't mean to
cheat, but it was still cheating anyhow.
     That was thirty-eight years ago when I was fifteen. I have never told anyone about it before, nor
 have I tried to explain to myself why not.
     The obvious     15 _   is that I could not admit I had seen the title without admitting that I had been
looking at the things on his desk. But there must have been more behind it. Whatever it was, it has
become a good example of how a little mistake can trap you in a more serious moral corner.