阅读理解
C
My daughter Eyen is ten years old. She is in Grade Three in a primary school. She is a cute girl though(虽然) she has some strange ideas sometimes.
One day she asks me, “Mum, what's your favourite subject?” I think for a while(一会儿) and answer，“It is difficult to tell. I love singing, so music is my favourite. And I am good at English. My history teacher also says I am excellent. Well, I can say I don't like science. But science is important for us, you know. So you must do well in it. What is your favourite subject, Eyen? Tell me something about your subject, dear.”
“I like Chinese. It is easy. I like English because my English teacher likes me very much. I can't stand maths. It's serious and sad(悲哀的).”
“Do you mean(意味)your maths teacher is serious and sad?”
“No, it is maths, not the maths teacher.”
“Why do you think so?”
“Because maths has so many problems! Isn't it sad all day?”
为奇函数，该函数的部分图 像如图所示，
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分别为最高点与最低点，且
，则该函数图象的一条对称轴为（ ）