13．
| two move he student ring young answer when silence angry |
I took up my first job as a teacher．The （71）students in my class were about sixteen or seventeen years old，only several years （72）younger than me．In fact，some of them looked older and seemed more like grown-ups．And some of them even didn't listen to me carefully in the class．
The classroom was on the （73）second floor and it was directly above the street．One day，I was writing on the blackboard （74）when I heard a sudden change in the noise behind me．There was a man standing in the room with half an apple in （75）his right hand．
"Who threw this？"he shouted，looking around the class （76）angrily．
"I beg your pardon？"I said．"Someone threw this apple out of the window，"he said，"It landed on my car．"
"Who threw the apple out of the window？"I shouted to the class．There was no （77）answer．
"I want the one who threw this，"said the man，"I will be waiting outside for you．"And then he left，slamming（摔） the door．
The students were （78）silent in class and I went on with the lesson．
At the end of every lesson，as the bell rang，usually the class were all gone before it finished （79）ringing leaving me saying"That's all for today．"to an empty room．
This time，when the bell went for the end of the lesson，no one （80）moved．"That's all for today．"I said．"You go first，sir．"said one of the boys．It made a nice change，being first out．
