题目内容：

If you want to slow aging, you might want to eat less. This finding is good news---if you were a mouse. The researchers studied mice, not people.

John Price and other researchers studied two groups of mice. One group was able to eat as much as it wanted. The researchers limited what the mice in the other group ate. Their diet had 35 percent fewer calories than the first group of mice.

Price says the mice with the diet restrictions were “more energetic and suffered fewer disease.” They were not just living longer but seemed to stay younger for a longer period of time.

The researchers found that fewer calories slow down a natural mechanism in cells called ribosomes. Price explains that ribosomes are responsible for making important proteins in the cells. But with fewer calories, they slow down. This gives the cells more time to repair themselves.

The researchers say ribosomes use from 10 to 20 percent of the cell’s energy to make those proteins. Price wrote that “because of this, it is impractical to destroy an entire ribosome” when it starts to break down. However, “repairing individual parts of the ribosome on a regular basis enables ribosomes to continue producing high quality proteins for longer than they would otherwise. This top quality production, in turn, keeps cells and the entire body functioning well.”

Price said, “ribosome is a very complex machine, like a car.” They need “maintenance to replace the parts that wear out the fastest. When tires wear out,” he explained, “you don’t throw the whole car away and buy a new one. It costs less to replace the old tires.”

“Food,” he said, “isn’t just material to be burned---it’s a signal that tells our body and cells how to respond.” Price said the findings help to explain how exactly our bodies age. And this may “help us make more educated decisions about what we eat.”

1.What can we know about the mice with limited calories from the study?

A. They can keep healthy easily

B. They need more energy to be active

C. They can look younger than they are

D. They will live a longer life like humans

2.What will happen to ribosomes if there are fewer calories?

A. They will completely break down

B. They make proteins in the cells slowly

C. They will produce high quality proteins more

D. They may need more time to repair themselves

3.Price explained the ribosomes’ role of repairing themselves by _________.

A. telling a story

B. listing basic data

C. making comparisons

D. experimenting on mice

4.What does the text mainly deal with?

A. Food decides how long you live

B. Can you slow down your aging process?

C. Eating less may help you live longer

D. Should your diet be reduced for your health?