New research led by the University of Colorado Boulder has found the engineering secrets behind what makes fish fins (鱼鳍) so strong yet flexible. The team’s findings could one day lead to new designs for airplane wings that change their shape with the push of a button.

Francois Barthelat, senior author of the study, noted that fins can “do wonders” even though they don’t contain a single muscle. “A fin is made of many ways,” said Barthelat. “Each of those rays can be controlled individually just like your fingers, but there are 20 or 30 rays in each fin.”

Barthelat and his colleagues used a range of approaches, including computer simulations and 3D-printed materials, to dive deep into the secrets of the structures. They reported that the key to fish fins may lie in their unique design. Each ray in a fin is made up of multiple segments (段) of a hard material that lie on top of much softer collagen (胶原), making rays the perfect balance between flexibility and strength.

He and his team decided to use computer simulations to examine the mechanical functions of fins. They discovered that those segments can make all the difference.

“Pretend for a moment,” Barthelat explained, “that fish fins are entirely made up of collagen. They could bend easily, but wouldn’t give fish much pulling force in the water. Rays made up of solid materials would have the opposite problem — they’d be too hard.”

The researchers further tested the theory by using a 3D printer to produce model fish fins made from plastic, some with hinges (铰链) built in and some without. The team found that the segmented design provided better combinations of strength and flexibility.

“We like to pick up where the biologists and zoologists have left off, using our background in the mechanics of materials to further our understanding of the amazing characteristics of the natural world,” Barthelat said.

【小题1】Which of the following can describe the new research according to the first paragraph?

A．Beneficial

B．Traditional.

C．Typical.

D．Commercial.

【小题2】Why are fingers mentioned in Paragraph 2?

A．To show the number of rays in a fish fin.

B．To show rays of fish fins can work individually.

C．To show the shape of rays in fish fins.

D．To show rays of fish fins can do.

【小题3】What has an important effect on the mechanical functions of fish fins?

A．The amount of collagen.

B．The combination of hard materials and collagen.

C．The water fish live in.

D．The muscle in fish fins.

【小题4】What may happen if fish fins are completely made of collagen according to the text?

A．Fish can’t bend.	B．Fish can’t live in the water.
C．Fish can’t keep balance.	D．Fish can’t swim fast.