Have you ever noticed that your fingers are wrinkled （有皱纹的） when you've just finished swimming or（1） 　    　cloths？It seems（2） 　    　your hands have aged 30 years in a short time.But is this an accident？Or is it something that nature has built into our bodies？

   The wrinkles looked a bit（3） 　    　 the patterns on the bottom of the running shoes.So （4） 　    　made a guess that wrinkles on fingers might be able to help the hands hold things better.

   To test this，researchers asked 20 people to pick up marbles （弹珠） from water（5） 　    　their hands.But（6） 　    　they started to pick up the marbles，half the people had to keep their hands in water for half an hour.

   The researchers discovered the people who had wrinkled fingers completed the task faster that those whose hands were dry.But when they（7） 　    　to move dry marbles，all the people performed the same，no matter whether（8） 　    　 had the wrinkled fingers or not.

Our ancestors might not play with marbles，but wrinkled fingers could make（9） 　    　easier for them to climb around in the wet forests and catch fish from（10） 　    　.

   Similarly，our feet （11） 　    　get wrinkled in water.This may develop from our ancestors' need to run（12） 　    　 the wet ground.

   But the question is，if wrinkled fingers are so helpful， （13） 　    　don't our hands just stay that way all the time？In fact，there（14） 　    　several disadvantages about wrinkled fingers.They make us feel（15） 　    　.And wrinkled fingers don't have enough sense of touch.

（1）

A．

making

B．

washing

C．

folding

（2）

A．

that

B．

which

C．

what

（3）

A．

after

B．

like

C．

into

（4）

A．

science

B．

scientific

C．

scientists

（5）

A．

with

B．

by

C．

from

（6）

A．

after

B．

before

C．

while

（7）

A．

ask

B．

are asked

C．

were asked

（8）

A．

we

B．

they

C．

you

（9）

A．

this

B．

that

C．

it

（10）

A．

rivers

B．

roads

C．

skis

（11）

A．

also

B．

too

C．

either

（12）

A．

under

B．

on

C．

in

（13）

A．

how

B．

which

C．

why

（14）

A．

are

B．

have

C．

is

（15）

A．

powerful

B．

enjoyable

C．

uncomfortable