阅读理解

    I've loved my mother's desk since I was just tall enough to see above the top of it when Mother sat doing letters. Looking at the ink bottle, pens and white paper, I decided that the act of writing must be the most wonderful thing in the world.

    Years later, during her final illness, Mother kept different things for my sister and brother, “But the desk,” she said again, “is for Elizabeth.”

    I never saw her get angry, and never saw her cry. I knew she loved me, and she showed it in action. But as a young girl, I wanted heart-to-heart talks between mother and daughter. They never happened and a gulf opened between us. I was “ too emotional (易动感情的) ”, but she lived “on the surface”.

    As years went by, I had my own family. I loved my mother and thanked her for our happy family. I wrote to her in careful words and asked her to let me know that she did forgive (原谅) me.

    I posted the letter and waited for her answer, but it didn't come. I wondered if the letter had even got to her. I only knew that I had written it, and I could stop trying to make her into someone she was not.

    Now the present of her desk told me that she was pleased that writing was my chosen work, though she had never been able to. I cleaned the desk carefully and found some papers inside … a photo of my father and a one-paper letter, folded (折叠) and refolded many times.

    Give me an answer, my letter asks, in any way you choose. Mother, you always chose the act that speaks louder than words.

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下列各式由左边到右边的变形中,属于分解因式的是(　　)