题干

如图所示是一款行李小拖车,车架及丁字腿均采用截面30mmX30mm的方形钢管制作。为减少收纳空间,要求丁字腿可以翻转。请设计车架和丁字腿间的连接件,设计要求如下:

A.丁字腿翻转收拢后紧贴车架并能固定

B.丁字腿打开后于车架垂直并能固定

C.连接件采用厚3mm,长和宽足够大的钢板制作,其余零件自选

D.结构简单操作方便

根据上述设计要求,完成以下任务

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同类题4

请认真阅读下列短文,从短文后各题所给的A、B、C、D四个选项中,选出最佳选项。

C

    If you want to disturb the car industry, you'd better have a few billion dollars: Mom-and-pop carmakers are unlikely to beat the biggest car companies. But in agriculture, small farmers can get the best of the major players. By connecting directly with customers, and by responding quickly to changes in the markets as well as in the ecosystems(生态系统), small farmers can keep one step ahead of the big guys. As the co-founder of the National Young Farmers Coalition (NYFC, 美国青年农会)and a family farmer myself. I have a front-row seat to the innovations among small farmers that are transforming the industry.

    For example, take the Quick Cut Greens Harvester, a tool developed just a couple of years ago by a young farmer, Jonathan Dysinger, in Tennessee, with a small loan from a local Slow Money group. It enables small-scale farmers to harvest 175 pounds of green vegetables per hour—a huge improvement over harvesting just a few dozen pounds by hand—suddenly making it possible for the little guys to compete with large farms of California. Before the tool came out, small farmers couldn't touch the price per pound offered by California farms. But now, with the combination of a better price point and a generally fresher product, they can stay in business.

    The sustainable success of small farmers, though, won't happen without fundamental changes to the industry. One crucial factor is secure access to land. Competition from investors, developers, and established large farmers makes owning one's own land unattainable for many new farmers. From 2004 to 2013, agricultural land values doubled, and they continue to rise in many regions.

    Another challenge for more than a million of the most qualified farm workers and managers is a non-existent path to citizenship — the greatest barrier to building a farm of their own. With farmers over the age of 65 outnumbering(多于)farmers younger than 35 by six to one, and with two-thirds of the nation's farmland in need of a new farmer, we must clear the path for talented people willing to grow the nation's food.

    There are solutions that could light a path toward a more sustainable and fair farm economy, but farmers can't clumsily put them together before us. We at the NYFC need broad support as we urge Congress to increase farmland conservation, as we push for immigration reform, and as we seek policies that will ensure the success of a diverse and ambitious next generation of farms from all backgrounds. With a new farm bill to be debated in Congress, consumers must take a stand with young farmers.