阅读理解。

    I arrived at my mother's home for our Saturday family dinner. The smells of food flew over from the kitchen. Mother was pulling out quilt after quilt from the boxes, proudly showing me their beauties. I knew they were all made herself. She was preparing for a quilt show on TV. When we began to fold and put them back into the boxes, I noticed something at the bottom of one box. I pulled it out. “What's this?” I asked.

“Oh?” Mom said, “That's Mama's quilt.”

    I spread the quilt. It looked as if a group of school children had made the pieces together.

 “Grandmother made this?” I asked in surprise. My grandmother was a master at making quilts. This certainly didn't look like any of the quilts she had made.

  “Yes, right before she died. I brought it home with me last year and made some changes,” Mom said, “I'm still working on it. See, this is what I've done so far.”

     I looked at it more closely. She had made a line straight(直的). At the center of the quilt， she had stitched a piece of cloth with these words:    “My mother made many quilts. She didn't get all lines straight. But I think this is beautiful. I want to see it finished. Her last quilt.”

“Oh, this is so nice, Mom.” I said. I was sure now that by completing my grandmother's quilt, my mother was honoring her own mother. I realized that I held in my hands a family treasure. It started with the loving hands of one woman, and continued with the loving hands of another.

阅读理解。

    I arrived at my mother's home for our Saturday family dinner. The smells of food flew over from the kitchen. Mother was pulling out quilt after quilt from the boxes, proudly showing me their beauties. I knew they were all made herself. She was preparing for a quilt show on TV. When we began to fold and put them back into the boxes, I noticed something at the bottom of one box. I pulled it out. “What's this?” I asked.

“Oh?” Mom said, “That's Mama's quilt.”

    I spread the quilt. It looked as if a group of school children had made the pieces together.

 “Grandmother made this?” I asked in surprise. My grandmother was a master at making quilts. This certainly didn't look like any of the quilts she had made.

  “Yes, right before she died. I brought it home with me last year and made some changes,” Mom said, “I'm still working on it. See, this is what I've done so far.”

     I looked at it more closely. She had made a line straight(直的). At the center of the quilt， she had stitched a piece of cloth with these words:    “My mother made many quilts. She didn't get all lines straight. But I think this is beautiful. I want to see it finished. Her last quilt.”

“Oh, this is so nice, Mom.” I said. I was sure now that by completing my grandmother's quilt, my mother was honoring her own mother. I realized that I held in my hands a family treasure. It started with the loving hands of one woman, and continued with the loving hands of another.

请画出图中重物G所受重力的示意图和拉力F的力臂(用L把力臂表示出来)。