I must return the two books to the library. I _____ them for 20 days.

John is a famous writer now.But he said he was not a   【小题1】  student when he was young.He was often late for    【小题2】  and didn’t like doing his homework.
Sometimes, he slept in class while the teacher was teaching.He didn’t understand much,   【小题3】 he always thought he understood everything.One day the teacher 【小题4】  the students a question, ‘When Jack was ten years old,  【小题5】 brother Bob was twenty.Jack is fifteen now and   【小题6】  is his brother Bob?’ John said, ‘ That’s easy.Bob is twice as old as Jack.So he is now thirty.’
Another time, the   【小题7】  in a science class asked, ‘ When it thunders（打雷）,   【小题8】  do we always see the light before we   【小题9】  the sound?’ ‘But, Miss,’ said John quickly.‘ Don’t you    【小题10】 our eyes are in front of our ears?’

____ the end, they arrived in the city ____the morning of June 20, 2005. 

A. in; at    B. By; on    C. At; in    D. In; on

Last week I went to a supermarket. After I  36  the bill and was passing through the door, the alarm suddenly started to ring. Suddenly, a young guard ran toward me and ordered me to  37 him. I felt so upset and   38 . He took me to a small room, but I was   39  frightened that I stopped at the door. Finding me  40to enter the room, he shouted that I had to go into the room.
He closed the door. I thought he was going to hurt me. Suddenly, a   41  voice said in my ear: “Take out the things you’ve stolen!” “I stole nothing.” I said. “Do as I tell you. If we find them, you’ll be in trouble.” “There is nothing.” I answered. “I didn’t take anything.” I said, taking everything out of my pockets and bag.
  42  this point, a guard came in and asked a salesgirl to   43  me.   44 , they found nothing.
But they didn’t believe that I hadn’t stolen anything. So the young guard ordered me to pass through the door alarm again.
I was   45 when it rang again. I felt   46  and burst into tears. I didn’t know how to prove   47  I was innocent(清白的).
They made me go into the small room again.
“Take out the stolen things quickly,  48  we will dial 110.” They said.
“OK, call the police. I’ m not afraid.” I said  49.
Suddenly,  they  50 their tone. After a while, a salesgirl asked me to raise my feet. I did   51  she had told me. There was a label (标签) on the bottom of my shoe. That was it! That was the  52 thing that had brought me such great trouble. But it  53my innocence.（清白）
After that, they 54  to me in the small room, But they should have apologized 55 , shouldn’t they? A lot of people were there when I was taken away. What did they think of me?

–When did the earthquake of Ya’an happen?

–It happened _______ April 20, 2013.

A．at               B．in                C．on               D．to