题干

“探究二力平衡的条件”实验目的:物体只在两个力的作用下,分别处于静止状态或____ 状态时,探究____ 的关系。在“探究杠杆平衡的条件”实验中,为得出实验结论,需多次改变杠杆受到作用力的大小、方向和____ ,使杠杆始终在____ 位置保持平衡。

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匀速直线运动,二力,作用点,水平

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    I was never very neat, while my roommate Kate was extremely organized. Each of her objects had its place, but mine always hid somewhere. She even labeled(贴标签) everything. I always looked for everything. Over time, Kate got neater and I got messier. She would push my dirty clothing over, and I would lay my books on her tidy desk. We both got tired of each other.

    War broke out one evening. Kate came into the room. Soon, I heard her screaming, “Take your shoes away! Why under my bed!” Deafened, I saw my shoes flying at me. I jumped to my feet and started yelling. She yelled back louder.

    The room was filled with anger. We could not have stayed together for a single minute without a phone call. Kate answered it. From her end of the conversation, I could tell right away her grandma was seriously ill. When she hung up, she quickly crawled(爬) under her covers, weeping. Obviously, that was something she should not go through alone. All of a sudden, a warm feeling of sympathy rose up in my heart,

    Slowly, I collected the pencils, took back the books, made my bed, cleaned the socks and swept the floor, even on her side. I got so into my work that I even didn't noticed Kate had sat up. She was watching, her tears dried and her expression one of disbelief. Then, she reached out her hands to grasp mine. I looked up into her eyes. She smiled at me. “Thanks.”

    Kate and I stayed roommates for the rest of the year. We didn't always agree, but we learned the key to living together: giving in, cleaning up and holding on.