Have you ever noticed that your fingertips are winked when you’ve just finished swimming or washing dishes? It seems as if your hands have aged 30 years in a second. But is this an accident? Or is it something that nature has built into our bodies?
If your finger’s wrinkling up had no use at all, “ it wouldn’t need to.” Professor Tom Smulders from Newcastle University, UK, told BBC News. By studying wet fingers closely, Smulders and his partners found that the wrinkles looked a bit like the patterns on the car tire or on the bottom of the running shoes. So they made a guess that wrinkles on fingers might be able to help the hand hold things more tightly.
To test this, researchers asked 20 people to pick up marbles from water with their hands. But before they started, some of the people had to keep their hands in water for half an hour.
The researchers found that the people with wrinkled fingers completed the task the task faster than those with dry hands. But when they were asked to move dry marbles, all the people performed equally well, no matter they had the wrinkled fingers or not.
Our ancestors might not have played with marbles, but wrinkled fingers could have made it easier for them to climb around in the wet forests and catch fish from rivers, researchers say.
Similarly, our toes also get wrinkled in water. This may have developed from our ancestor’s need to run on wet ground.
But the question is, if wrinkled fingers are so helpful, why don’t our hands just stay that way all the time? Researchers explained that wrinkling has its disadvantage: wet fingertips are far less sensitive than smooth ones, reducing our sense of touch.
【小题1】What does the underlined world “this ” in the third paragraph refer to?

Every culture has a recognized (公认的) point when a child becomes an adult, when rules must be followed and tests passed.
In China, although teenagers can get their ID cards at 16, many only see themselves as an adult when they are 18. In the US, where everyone drives, the main step to the freedom of adult life is learning to drive. At 16, American teens take their driving test. When they have their license（证）, they drive into the grown-up world.
"Nobody wants to ride the cheese bus to school," said Eleanor Fulham, 17. "It's like you're not cool if you don't have a car," she said.
According to a recent research, 41% of 16 to 19 year olds in the US own cars, up from 23% in 1985. Although, most of these cars are bought by parents, some teens get part-time jobs to help pay.
Not all families can afford cars for their children. In cities with undergrounds and limited(有限的) parking, some teenagers don't want them. But in rich areas outside the city, if there are no undergrounds, and bicycles are more for fun than cars, it is strange for a teenager not to have a car.
But police say 16-year-olds have almost three times more accidents than 18 and 19-year-olds. This has made many parents stop before letting their kids drive. They need to wait until they are more experienced.
Julie Susiana, of Virginia, decided that her son Chad, 15, will wait until he is 17 to apply for his learner's permit (许可)
Chad said he has accepted his parents' decision, although it has caused some laughing from his friends. "They say that I am unlucky," he said. "But I'd rather be alive than driving, and I don't really trust my friends on the road either."
In China as more families get cars, more 18-year-olds learn to drive. Will this become a big step to becoming an adult?
【小题1】16-year-old drivers have more accidents possibly because _______.

----I wonder_______.

----Of course. He began to prepare for it last month.

A．when will he give back the magazine to the library

B．whether he has prepared for the writing competition

C．what was he talking about with his friends

D．where he is going to hold the English party

He hasn’t decided _______ to go by bus or by train.

A．if                B．whether          C．how              D．that