阅读下面短文， 掌握大意，从每小题所给的A、B、C、D四个选项中选出最佳选项。
Monday began as usual. It wasn't until the third- graders reached their classroom that they noticed a new 1 . She was tall and straight with grey hair and witch's cold eyes, carrying a plant and a book.
"I'm Miss Orville. I've taught for forty- six years," she warned."I know lots of your tricks (恶作剧), 2 I advise you to try none. You' re to be in my charge until your teacher returns. Since I don't know you, let me look at your 3 first. Completed it? Take it out. Now!"
" You call THIS homework?" R-r- rip! A page was torn out and thrown at 4 owner. " Do it again."
Roger opened his schoolbag. 5 , it fell off. Books, pencils spilled out. Cards, toys, balls..." Ah, we've come to play, have we?" She fixed her witch's gaze on him.
The third grade was the last to 6 school. The children looked strangely defeated. Roger pulled his mother," We don't have a new teacher but a witch(巫婆) named Miss Awful. Hurry, I have much homework!"
Finally, on Friday Miss Orville said, " Your teacher will return. This afternoon will be my7 class." At lunch, the third grade talked about nothing except how to 8 Miss Awful. Joey suggested," We could tie a rope in front of the door. She would fall down if she walked over."
" No. She's old," Roger said." We 9 hurt her like that."
" How about taking off the 10 of that plant?" advised someone.
Roger didn't want to do that, not understanding why. It was a feeling he couldn't explain.
" Well, you worked hard last week," Miss Orville began her class. " Attending school is like a priceless gift. If I've been 11 , it was for your benefit. The world needs good people..."
She stopped suddenly, staring at the plant 12 its leaves. She faced the class, looking sad.
" Whoever is responsible, I only wish you to be 13 ."
After class, she said goodbye to the students. They ran out, some regretful, some silent, others cheerful. Only Roger stayed behind. He 14 her, rubbing his hand up and down his coat." Yes?" Miss Orville asked. " Flower, f-l-o-w-e-r. Castle, c-a-s-t-l-e. I've learned 15 you taught us." He smiled to Miss Awful whose eyes were wet.
