题目内容：

The days of having to carry a phone charger everywhere could soon be over. Michigan researchers have revealed a major breakthrough in harvesting energy from human motion.

They say it could lead to smartphones powered for a week by the motion of a swipe (重击).

Michig an State Univ ersity’s low -cost devic e, known as a nanogenerator, has already been tested. Scientists success fully operated an LCD touch screen, a bank of 20 LED lights and a flexib le keyboard, all with a simple touching or pressing motion and without the aid of a battery. The groundbreaking findings, published in the journal Nano Energy, suggest “We’re on the path tow ard wearable devices powered by human motion,” said Nelson Sepulv eda, associate professor of electrical and computer engineering and lead researcher of the project.

“What I foresee, relatively soon, is the capability of not having to charge your cell phone for an entire week, for example, because that energy will be produced by your movement,” said Sepulveda, whose researchis funded by the National Science Foundation.

Electrical energy is created when the device is compressed by human motion. The completed device is as thin as a sheet of paper. The device used to power the LED lights was palm-sized, w hile the device used to power the touch screen was as small as a finger. Advantag es such as being lightweight, flexib le and low -cost could make it a promis ing and alternative method in the field of Mechanical-energy harvesting.

The device also becomes more powerful when folded. Sepulveda said, “You can start with a large device, but when you fold it once, and again, and again, it’s much smaller and has more energy. Now it may be small enough to put in a specially made heel of your shoe so it creates power each time your heel strikes the ground.”

Sepulveda and his team are also develop ing technology that w ould transmit the power generated by the heel strike to, say, a w irelessheadset.

1.The underlined word “device” in the second paragraph probably refers to .

A. a piece of equipment    B. a special kind of smartphone

C. a touch screen    D. a flexible keyboard

2.What can we learn about Nelson Sepulveda in the passage?

A. He works as a journalist writing for Nano Energy.

B. He plays a major role in the project of the nanogenerator.

C. He invented a type of battery-free smartphone.

D. He collects funds for the National Science Foundation.

3.From the passage we know that the nanogenerator .

A. becomes more powerful when kept flat

B. has already come into market in the USA

C. is lightweight and flexible though expensive

D. makes it possible to produce power by walking

4.The purpose of the passage is to .

A. persuade people to buy the device

B. bring in a new way to save energy

C. introduce a breakthrough in science

D. honor Nelson Sepulveda for his contributions