题干

如图1所示,修正带是通过两个齿轮的相互咬合进行工作的.其原理可简化为图2所示模型.则A、B两点具有相同的(   )

A:角速度

B:周期

C:向心加速度的大小

D:线速度的大小

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D

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    A few years ago, I took a sightseeing trip to Washington, DC. I saw many of our nation's treasures, and I also saw a lot of our fellow citizens on the street —1 ones, like beggars(乞丐)and homeless folks.

    Standing outside the Ronald Reagan Center, I heard a voice saying: “Can you help me?” When I2, I saw an elderly blind woman with her hand 3. In a natural reaction, I 4 into my pocket, pulled out all of my loose change and placed it in her hand without even looking at her. I was 5 at being bothered by a beggar.

    But the blind woman smiled and said: “I don't want your money. I just need help finding the6.”

    In an instant, I realized what I had done. I had acted with prejudice(偏见)— I'd 7 another person8for what I believed she had to be.

    I hated what I saw in myself. This incident brought back my basic belief. It 9 me that I believed in being modest even though I'd lost that 10 for a moment.

    The thing I had forgotten about myself is that I am a (n)11. I left Honduras and arrived in the U. S. at the age of 15. I started my new life with two suitcases, my brother and sister, and a strong mother. Through the 12, I have been a dish washer, roofer, mechanic, cashier and pizza delivery driver 13 many other humble hobs, and14 I became a network engineer.

    In my own life, I have15 many acts of prejudice. I remember a time, at the age of 17 — when I was a busboy, I heard a father tell his little boy that if he did not do well on school, he would 16 like me. I have also seen the same treatment of family and friends, so I know what it's like, and I should have known 17.

    But now, living my American middle class lifestyle, it is too easy to forget my past, to forget who I am and where I have been, and to lost sight of where I want to go. That blind woman cured me of my18. She reminded me of my belief in being humble, and to always keep my eyes and heart open.

    19, I helped that woman to the post office. And in writing this essay, I hope to thank her for the20 lesson she gave me.