题目

阅读下面材料，根据其内容和所给段落开头语续写两段，使之构成一篇完整的短文，续写的词数应为150左右。When I was ten years old, I lived with my family in a small house in rural South Jersey. I often accompanied my mother to the A&P to buy groceries. Without a car, we walked, and I would help her carry the bags.My mother had to shop every carefully, as she was a waitress, and her salary barely sustained (勉强维持) us. One day, while she was weighing prices, a promotional display for the World Book Encyclopedia (百科全书) caught my eye. The v 如图2所示，质量为m的物体悬挂在轻质的支架上，斜梁OB与竖直方向的夹角为θ。O、A、B三处皆铰链相连，设水平横梁OA和斜梁OB作用于O点的弹力分别为F1和F2。以下结果正确的是A．　　　　　　B．C．　　　　　　D．