题干

图甲为一种测定油箱内油量的装置,把电流表刻度盘改为相应的油量体积数,就可以直接读出油箱中的油量.当油箱中的油量减少时,浮子就会带动滑杆使电流表的示数变小.现将电流表换成电压表,请用乙图设计一个电路,使油箱中的油量消耗到最少时,电压表的示数减小到零.

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解:使滑动变阻器的上半部分电阻与R0串联,电压表并联在R两端,如下图所示:

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     The answer to protecting and saving marine(海洋) wildlife can start with cutting back on something Americans use every day—plastic drinking straws. Actor Adrien Grenier, best known for playing Vincent Chase in 2015 movie Entourage, has launched a campaign to reduce the amount of single-use plastic usage in this country in order to protect and save marine wildlife and the environment. Plastic drinking straws are among many single-use plastic products contributing to the shocking loss of marine life, but they're a great place to start because they're something Americans are using by the hundreds of millions without any awareness that they're so damaging.

     According to Ecocycle, an international environmental organization, Americans use more than 500 million straws daily, which are enough to fill 127 school buses each day, and they can’t be recycled. They means plastic straws end up in landfills or oceans, where fish and other marine wildlife mistake the small bits for food and swallow them. After seeing a photo of a whale beached on the shore with a belly full of plastic, Grenier felt the inspiration to launch the Lonely Whale Foundation, hoping to inspire and educate others on the challenges facing marine life.

     Along with stopping the use of straws, Grenier hopes to educate consumers on the dangers of other single-use plastic items such as grocery bags and water bottles. While many Americans use these plastic products in their daily life, there are more sustainable alternatives that can help protect the environment. Ecocycle recommends the use of straws made from stainless steel, glass, and even bamboo instead of plastic. You can buy a number of these environmentally friendly straws online and in stores.