A．he found the exact cause of learning disabilitiesB．th……
第三篇
Learning Disabilities Learning disabilities are very
common. They affect perhaps 10 percent of all children. Four times as many boys
as girls have learning disabilities. Since about 1970, new
research has helped brain scientists understand these problems better.
Scientists now know there are many different kinds of learning disabilities and
that they are caused by many different things. There is no longer any question
that all learning disabilities result from differences in the way the brain is
organized. You cannot look at a child and tell if he or she has
a learning disability. There is no outward sign of the disorder. So some
researchers began looking at the brain itself to learn what might be
wrong. In one study, researchers examined the brain of a
learning-disabled person who had died in an accident. They found two unusual
things. One involved cells in the left side of the brain, which control
language. These cells normally are white. In the learning disabled person,
however, these cells were gray. The researchers also found that many of the
nerve cells were not in a line the way they should have been. The nerve cells
were mixed together. The study was carried out under the
guidance of Norman Geschwind, an early expert on learning disabilities. Doctor
Gesehwind proposed that learning disabilities resulted mainly from problems in
the left side of the brain. He believed this side of the brain failed to develop
normally. Probably, he said, nerve cells there did not connect as they should.
So the brain was like an electrical device in which the wires were
crossed. Other researchers did not examine brain tissue.
Instead, they measured the brain’s electrical activity and made a map of the
electrical signals. Frank Duffy experimented with this technique
at Children’s Hospital Medical Center in Boston. Doctor Duffy found large
differences in the brain activity of normal children and those with reading
problems. The differences appeared throughout the brain. Doctor Duffy said his
research is evidence that disabilities involve damage to a wide area of the
brain, not just the left side.
Doctor Dully believed that______.
A．he found the exact cause of learning disabilities B．the problem of learning disabilities did not lie in the left side of the brain C．the problem of learning disabilities resulted from the left side of the brain D．the problem of learning disabilities was not limited to the left side of the brain
