题目内容：

    When you think of batteries, you’ll likely think about them powering up remote controls, cellphones, flashlights and toys. But some people carry a battery around in their body to power a pacemaker (起搏器). It isn’t really pleasant and easy to carry batteries because they need to be replaced so often and they can leak poisonous chemicals. A battery-powered pacemaker may become a thing of the past, thanks to a new technology developed by UCLA researchers: a biological supercapacitor (超级电容器), which is thinner than several hairs.

Teams of researchers at UCLA and the University of Connecticut published a paper in a journal explaining their new invention. The supercapacitor is made from a carbon material, and coated with human-like proteins that act as electrodes (电极). But what makes the device different is that it is powered by an energy harvester that changes body heat and movement in the blood into energy.

Those traditional pacemakers are six to eight millimeters thick. They are much bigger. The new supercapacitor, which, due to its lack of battery, is only one micrometer thick. This “little” feature could benefit the new pacemaker’s energy efficiency, researchers stated. Also, unlike other batteries used in medical treatments, the supercapacitor can bend and twist in the body without suffering damage.

Though they’ve not been widely used in the medical world, supercapacitors have the ability to serve as a safer and more efficient medical device than the traditional battery-operated devices, the researchers believe.

“In order to be effective, battery-free pacemakers must have supercapacitors that can get, store and transport energy. However, commercial supercapacitors are too slow to make them work,” said Maher El-Kady, a UCLA researcher and a co-author of the study. “Our research focused on the custom-designed supercapacitor to capture energy effectively, and finding a way to make it exist together successfully with the human body.”

1.What do we know about traditional pacemakers?

A.They are very popular with users.

B.They can do harm to the users’ bodies.

C.They need to be replaced quite often.

D.They are really convenient to carry around.

2.What is special about the new supercapacitor?

A.It has electrodes on the outside.

B.It is made from a kind of protein material.

C.It can transform the energy from the body.

D.It helps save the carriers’ money and energy.

3.Which of the following makes the new pacemaker energy-efficient?

A.The small size.

B.The small battery.

C.The energy harvester.

D.The bending and twisting characters.

4.What is the best title for the text?

A.A New Technology to Downsize Batteries.

B.A New Battery-free Pacemaker.

C.A Smaller Battery-powered Pacemaker.

D.A Great Contribution Made by UCLA Researchers.