Question 5 is based on the news report you have just heard.

News Report Three

    Three university students in Santiago, Chile, have（5）developed a plant-powered device to charge their mobile phones. 

    The three engineering students（6）got the idea for the device while sitting in their school’s courtyard. Their invention is a small biological circuit they call E-Kaia. （7）It captures the energy which plants produce during photosynthesis—a process of converting sunlight into energy.

     A plant uses only a small part of the energy produced by that process. The rest goes into the soil. E-Kaia collects that energy. The device plugs into the ground and then into a mobile phone. 

    The E-Kaia solved two problems for the engineering students. They needed an idea for a class project. They also needed an outlet to plug in their phones. 

    One of the student inventors, Camila Rupcich, says the device changes the energy released from the plant into low-level power to charge phones. 

    The E-Kaia is able to fully recharge a mobile phone in less than two hours.

5. What did the three university students invent? 

解析：C。该题目为细节题。问题是：三名大学生发明了什么？原句出现在报道首句。根据问题关键词“ university students”定位文章出处：Three university students in Santiago, Chile, have developed a plant-powered device to charge their mobile phones. 三名智利圣地亚哥的大学生已经研发一种植物充电设备来为他们的手机充电。选项C）A plant-powered mobile phone charger，与原文信息一致。因此，此题目正确答案为C。