科学与技术

阅读理解

Passage 1

In 2018， a severe drought brought Cape Town close to “Day Zero”， when it could have become the world’s first major city to run out of water. Dam levels in South Africa’s Western Cape fell to below a fifth of capacity and the province suffered its worst water crisis in 100 years.

“The water supply was dwindling and it just wasn’t raining，” recalls Thinus Booysen， a professor at Stellenbosch University， who had created a device in 2015 designed to help homeowners cut their power usage. Seeking to reduce water waste， Booysen figured he could adapt the device to measure water usage instead of electricity use.

Soon， Booysen launched a start-up， Bridging the Internet of Things （BridgIoT）， to develop his idea. Called Count Dropula， the device reports water usage once a minute while many conventional devices only record data once an hour. The system uses an app in the user’s cellphone and sends short messages in real time. “Within minutes， we would be able to tell the user， ‘Something has burst， or something is leaking，’” he says.

Then Booysen discovered that a key issue was maintenance， with the poorest schools using by far the most water. Leaking toilets could waste 1，000 liters of water per day. “We found that the biggest problems are things like children not closing taps properly， but often that would be because the taps just don’t close，” Booysen explains. During the test， the invention saved one school more than three million liters of water in three months. Another reduced its water usage 55 percent in four months.

Businesses including Cape Talk radio station and Africa’s largest food company， Shoprite， became sponsors， partnering with the Western Cape Education Department to install （安装） test devices in 350 schools. They saved more than $2.7 million and almost 550 million liters of water in 17 months. Booysen has looked at expanding to government buildings， hospitals and hotels. There are plans to roll out the device across Africa.

1. What does the underlined word “dwindling” in Paragraph 2 probably mean？

A. Beginning. B. Continuing. C. Expanding. D. Decreasing.

2. What can we learn about Count Dropula？

A. It works smartly to help save water. B. It was designed by Booysen in 2015.

C. It will soon be tested in 350 schools. D. It cuts power usage efficiently.

3. What words can best describe Booysen？

A. Proud but determined. B. Careful and friendly.

C. Creative and caring. D. Strict but generous.

4. What will Booysen probably do next？

A. Become a member of Shoprite. B. Further promote his new invention.

C. Stop water pollution in Cape Town. D. Travel around Africa for better ideas.

Passage 2

Someday， you may no longer need to brush your teeth by hand. Instead， a group of billions of nanoparticles （纳米粒子） could automatically do it for you. It would be especially life-changing for those who find it difficult or impossible to hold and move a toothbrush.

Steager， an engineer at the University of Pennsylvania in Philadelphia， an inventor and dental researcher there， found a way to form the nanoparticles into long， skinny bristles （刷毛）， a lot like the ones on a toothbrush. But these bristles shape-shift to fit whatever surface they encounter.

The tooth-cleaning robot works due to two magnets （磁铁）. One goes each side of the teeth. The nanoparticles sit in a liquid between the magnets. When the magnets are turned off， the nanoparticles move randomly in the liquid. As soon as one magnet gets turned on， the nanoparticles gather together near its center. When the researchers turn on the other magnet and turn off the first one， the nanoparticles extend outward in long， skinny bristles. When there’s a tooth in the way， these bristles can’t stretch out as far as they want. So they push against the tooth’s surface. If there’s a gap between teeth， they push into the gap. Moving the magnets makes the bristles move against and between teeth. All that motion cleans the teeth. As a bonus， the nanoparticles also have strong power to kill viruses.

The new device is just a proof of concept. The researchers still need to turn it into a product that people will want to use. “There’s a lot of engineering to get from here to there， but every good idea needs to have a start，” says Steager.

1. What is special about the tooth cleaner？

A. It’s transformable. B. It’s water-proof.

C. It contains skinny bristles. D. It uses little energy.

2. What is Paragraph 3 mainly about？

A. The working principle. B. The magnets’ motion.

C. The virus-killing process. D. The bristles’ formation.

3. How does Steager feel about the future of the device？

A. Uncertain. B. Concerned. C. Confident. D. Disappointed.

4. What can be the best title for the text？

A. A Tooth-Cleaner Fighting Diseases B. A New Concept for a New Start