Gold and her colleagues were surprised that ____________.
1. it didn't take long to see the effect of smoking on the ling growth of teenagers
2. girls tended to be heavier smokers than boys
3. it took so many years before the effect of smoking could be studied
4. children started smoking much sooner than previously thought
Previous research has shown that youngsters who smoke are more likely to have coughs, asthma and bronchitis.
Now, experts have found that teen-age smoking actually seems to make boys' and girls'
lungs grow more slowly than usual, so they hold less air.