题干

小明家装修房屋,他和爸爸、妈妈一同到商店买木地板.售货员向他们宣传:硬度高的木地板质量最好,同时拿出A.B.C三种不同品牌木地板样品,用刀在三种木地板上刻划,然后极力推荐其中划痕最不突出的C品牌地板.小明看后对爸爸、妈妈说这种比较方法不科学,并详细说明应该怎样控制变量,进行实验比较.爸爸、妈妈听后露出了满意的笑容.

请根据学过的物理知识判断,在售货员所做演示中,影响木地板划痕深度的两个主要原因是:

________

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压力的大小,刀与地板接触面的大小(刀的锋利程度、用刀口或刀尖划地板).

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    On a rainy night three years ago my dear mom went to accompany her Lord. She did it her way.

    I got the call at work, and l headed home quickly. Mom and Dad lived on a small farm that they had owned since I was seven. I hated going there every weekend. There was nothing for a young girl to do but watch the one station on the old TV set, if the weather allowed reception.

    My mom, on the other hand, loved the peace and quiet of the land. The place was rural, with no indoor plumbing or heat. We had a big wood stove in the kitchen that did its best to heat the little farmhouse, but it always seemed cold and too quiet to me.

    In the evenings, my mom and I would sit for hours singing in the little kitchen. I sang the melody and Mom harmonized. Her favorite song was “Moon River” and we sang it over and over. Mom told me stories about how when I was a little girl I could sing before I could talk.

    As time passed, I had my own children and went to visit them every week or two. The kids loved the farm and the tractor rides with my dad. Me, well, I still hated the silence of the farm. While my mom loved to sit at her kitchen table and look out at her garden and flowers and retell all the old stories, I missed the hustle and bustle of my life at home. But I sat there listening quietly as she reminisced.

    Now, I sat back in the silence and the silence was deathly so I finally leaned over to turn on an old radio. Music always comforted me. My heart skipped a beat. “Moon River” was playing on the radio. I sat there wordless, with a tear running down my cheek, as I listened to every familiar note.