题目内容：

    The world’s elderly population is increasing. The number of older people ---those age 60 years or older ---is expected to double by 2050 and is growing faster than all younger age groups across the globe. That comes with an increasing need for caregivers which can provide 24-hour care, not only at hospitals or nursing homes, but also at private homes.

Already, caregiving robots are programmed to ask questions a nurse would ask and can keep an eye on patients for falls. These robotic assistants are expected to become increasingly marketable and reach 450,000 by 2045 because of the expected caregiver shortage in the USA.

“Unluckily, the hard structure of present caregiving robots prevents them from a safe human-robot interaction(互动), limiting their assistance to only social interaction and not physical interaction,” said Ramses Martinez, an assistant professor in Purdue’s College of Engineering . “After all, would you leave babies or old people in the hands of a robot?”

Recent advances in material science have enabled the production of soft robots with deformable (可变形的) bodies or the ability to reshape when touched , but today the complex design prevents the use of this technology at home .

However, Martinez and other researchers have developed a new design method which shows promise in enabling the production of soft robots using a 3D printer.

“The soft machines move like humans. Their ability to change their body structure and movement to adapt ( 适应 ) to a wide variety of environments will improve caregiving greatly,” says Martinez .

The researchers are looking for partners to test and bring their technology to market.

1.What does the underlined word “That” in Paragraph 1 refer to?

A.The younger age group

B.The group of older people

C.The population across the globe

D.The growth of the elderly population

2.What is the disadvantage of the present caregiving robots?

A.They can’t provide safe physical interaction

B.They can’t communicate with patients

C.They can’t watch patients for falls

D.They can’t provide 24-hour care.

3.What do we know about Martinez’s new design method?

A.It requires a special kind of 3D printer.

B.It makes the production of soft robots simpler.

C.It has been put onto the market.

D.It is hard for users to master.

4.What is the text mainly about?

A.The robot industry in the future

B.Effects of population ageing

C.Robots for the elderly created with 3D printers

D.The development of caregiving robots