(2019·石家庄重点高中摸底)When Gitanjali Rao shared how she likes "finding solutions to real problems"， it was hard to imagine this dynamic girl could settle a problem that had escaped scientists for years.

　　In just three months, Rao came up with a device that can replace the costly and lengthy tests currently used to reliably determine lead levels in our fresh water. Inspired by the current litigation(诉讼) in Flint, Michigan, a case of water pollution from 2014 until present, Rao designed a new testing system that resulted in her being named "America's top young scientist" for 2017.

　　Rao had been following the water problem for about two years. She was amazed by the number of people affected by lead pollution in water and wanted to do something to change this. Rao spent months trying to convince local high schools and colleges to give her lab time to continue her experiment. At home, Rao worked on her project in the "science room" she asked her parents to create for her. Rao has created a device that uses three parts: a cartridge, a Bluetooth reader and an app. To put it simply, the cartridge contains carbon nanotubes(纳米管) that react to lead. This reaction is then registered by the Bluetooth reader, which sends a signal to a mobile app that can tell you immediately if your water is safe to drink.

　　Rao appropriately named the device Tethys and is hoping to make a little improvement to get the device on the market. While we may not be aware of any lead pollution present in our aging pipelines, lead poisoning can cause delays in physical and mental development. With Rao believing that "the purpose of science is to make a difference"， her incredible invention could make a difference to millions of people in the United States.

　　语篇导读　一个女孩发明了一款可以检测水中铅含量的装置，从而解决了一个多年来科学家忽视的问题。

　　【熟词生义】lead　常用义：v.引领　生义：n.铅

　　put　常用义：v.放，安置　生义：v.表达

　　reader　常用义：n.读者　生义：n.阅读器

　　5．What do we know about Rao's device?

　　A．It's cheap and quick.

　　B．It's cheap and inaccurate.

　　C．It's expensive and reliable.

　　D．It's portable and time­consuming.

　　解析 A　推理判断题。根据第二段第一句可推知，与以前又贵又费时的设备相比，Rao所发明的设备既便宜又省时，与第三段最后一句相呼应，故选A项。

6．What made Rao have the idea of designing the device?