Children with autism(孤独症)have difficulty with social skills and communication．They often behave in limited and repeated ways and have what seem like unusual Strong interests．
Autism is more common in boys than girls．What causes it is not clear. Scientists are studying genes and possible environment influences．
Doctors usually cannot confirm a about three years old .Rebecca Landa is diagnosis of autism until a child is a researcher at the Kennedy Krieger institute and Johns Hopkins University School of Medicine in Maryland .Professor Landa wanted to find out what differences in development might be seen earlier．She led a new study that observed 235 babies between 6 and 36 months of age．
“At 6 months of age，the signs of some risk for developing communication and social delays，including autism，include motor delays．Like when you lay your baby on their back and you pull them by the arms gently into a seated position ,the baby’s head may nod back behind the shoulders，like poor head contr01．That does not mean that the baby is going to have autism，
but It does mean the baby needs to have some exercises to strengthen their body·And when they strengthen their body，they are better able to play with toys and engage with people， which then goes on to help them have better outcomes．
By the time a baby is one year old，signs of possible autism include difficulty In using words and not looking eye-to-eye or reaching out to other people·By 14 months，the baby might smile less and use language 1ess．However 'Professor Landa says these signs can be so small that they might be missed during fl short health exam．
It s important for parents to learn their children’s development，and if a parent is concerned about a child’s development，seek professional advice．
The earlier parents notice delays，she says，the sooner they call begin doing simple things that may help improve their child’s development．For example talking to the child about what they are doing，commenting when the child shows them something，and playing simple games that keep the child’s attention
28·What’s the best title of the passage?
A．Watching for Early Signs of Autism in Babies
B How to Confirm a Diagnosis of Autism
C Children with Autism Have Difficulty in Communication
D．Ways to Help Children with Autism to Recover
29·What can we learn from the third paragraph?
A.Landa has found ways to confirm a diagnosis of autism when a baby is about six months．
B.．Landa tried to find autism earlier by comparing．the differences as the baby grows up．。
C. Now doctors can confirm a diagnosis of autism before a child is three years old
D．Doctors observed 235 babies either 6 or 36 month．s of age under the guide of Landa ．
30·When a baby with signs of possible autism is a year and two months，he may______
A.avoid eye contact
B have difficulty in raising his head
C develop bad manners
D．hate to communicate with others
31．In which column could we find this passage?
A.Education B.Health．
C. Economies D.Entertainment