Can you walk in a straight line? The question is much more difficult to answer than you think. Believe it or not, your eyes and ears help you to walk!

A recent experiment held in Japan shows that it is almost impossible for people to walk exactly straight for 60 meters.

　　The Tokyo University of Agriculture and Technology asked 20 healthy men to walk as straight as possible for 60 meters at normal speed.

Each man had to wear socks soaked with red ink and walk on white paper fixed flat to the floor. The footprints showed that all walked in a winding rather than a straight line.

Researchers found that people readjust their direction of walking regularly. The amount of meandering（曲折前行） differed from subject to subject.

This suggests that none of us can walk in a strictly straight line. Rather, we meander, mainly due to a slight structural or functional imbalance of our legs. So steps by the left and right legs of a person are different.

As a result, although we may start walking in a straight line, several steps afterwards we have changed direction. Eyesight helps us to correct the direction of walking and leads us to the target.

Your ears also help you walk. After turning around a lot with your eyes closed, you can hardly stand still or walk straight. It's all because your ears are still spinning and can't help you keep your balance. Inside your inner ear is a structure containing liquids. Inside your ears are many minute hair-like structures that move around as the liquid flows.

When you spin the liquid inside also spins. The difference is that when you stop, the liquid continues to spin for a while. Dizziness（眩晕） is the result.

　　For the moment, although your eyesight tells you to walk in a straight line your brain listens to your spinning ears, thus you don't walk in a straight line!

1．When you walk for 60 meters, you         .

       A．can walk straight without effort           

       B．meander at first, and in while walk in a straight line

       C．can’t walk exactly straight at any time

       D．can almost not cover the distance in a straight line

2．Why most time can we only wind our way?

       A．Because our eyes direct us to.

       B．Because our ears direct us to.

       C．Because of a slight structural or functional imbalance of our legs.

       D．Because our eyesight and ears aren’t always in harmony with each other.

3．According to the research, we can be led to the target mainly due to         .

       A．our eyesight         B．our brain             C．our inner ear        D．our sense of direction

4．Which of the following can prove that your ears help you walk according to the passage?

       A．Your are always meandering most time, but you can arrive where you want to go.

       B．After you turn around a lot with your eyes closed, you almost can’t keep balance.

       C．When you walk to a target, you readjust your direction of walking regularly.

       D．You start walking in a straight line, several steps afterwards you’ll change direction.