阅读短文，从文后每小题A、B、C选项中选择最佳答案。
A
One day Vimala and her new friend. Mary, were playing at school. Mary was a very quiet and shy girl but Vimala liked her. While jumping, Mary's glasses fell off and broke. Just then the bell rang and they had to hurry to their science class.
“Oh dear, I'm going to be as blind as a bat. But we'd better hurry. It's Miss Lee's class, "said Mary.
At the start of the lesson, Miss Lee explained how to do the experiment to produce large eye crystals. Then she started to question the class. Nobody dared to give a wrong answer because Miss Lee was a very strict teacher Miss Lee held up a clamp(夹具) and said, "What do we use it for? What do we call it? All the girls looked down, while she looked at their heads for one to pick on. "Mary?" she finally asked.
Mary was sitting at the back of the class. She stood up and peered at Miss Lee, but she could not see clearly what the teacher was holding. She was nervous a bit and did not answer.
Miss Lee repeated her question. This time she spoke more slowly and there was anger in her voice.
"What is this used for?" she asked
Vimala saw storm clouds climbing up to Miss Lee's face. She knew that the storm was about to burst on Mary, so she put up her hand. Miss Lee paid no attention to her and stared through narrowed eyes at Mary, waiting for an answer.
Mary did not know what to say. She looked to her left and right for help. Too scared to say out that she couldn't see clearly, Mary hoped that if she kept quiet Miss Lee would ask somebody else.
Vimala guessed what was wrong, so she decided to take a risk. She jumped to her feet and said, "Excuse me. Miss Lee. Mary broke her glasses just before the lesson started. I don't think she can see the clamp clearly. "Then she sat down, praying (祈祷)that the ceiling would not fall on her.
“Oh!” Miss Lee said, a little surprised. She had thought that Mary was refusing to answer. Now that she understood, her anger faded away. “Thank you, Vimala.” she said. Then she turned to Mary and said, “Come and look at this.”
Mary left her chair and went to the front of the class.
“It's a clamp.” she said. "We can put it on a metal stand(支架) and use it to hold things in place.”
"Well, you got it right at last." Miss Lee said with a brief smile. But you'd better not do any experiments until your glasses have been repaired. You can watch Vimala while she does the experiment.
The storm clouds disappeared. The smile disappeared from Miss Lee's face and she continued with the lesson. Vimala winked at Mary who peered at her and smiled weakly.
