Directions; Complete the following passage by using the words in the box．Each word can only be used once Note that there is one word more than you need．
A．actually    B．suddenly    C．impact     D．fitness    E．memories
F．imaging    G．responsible     H．implications   I．boost     J．encouraging
If you want to 小题1:_ your child's results at school, you could do a lot worse than ensuring that they do plenty of exercise．Scientists have already shown that physical activity can make you cleverer．A team in America has used scans to show that an important part of the brain _小题2:_ grows in children who are fit．These youngsters tend to be more intelligent and have better _小题3:_ than those who are inactive．
Scientists also found that one of the most important parts of their brains was 12 per cent larger than those of unfit youngsters．They believe that _小题4:_ children to take exercise from a very young age could help them do better at school later．Researchers from the University of Illinois, in the U．S．, studied the brains of 49 children aged nine and ten using a magnetic resonance _小题5:_ scan, a technique which provides very detailed pictures of organs and tissues in the body．
They also tested the _小题6:_ levels of the children by making them run on a treadmill．The scientists found that the hippocampus（海马体）, a part of the brain _小题7:_ for memory and learning, was around 12 per cent larger in the fitter youngsters．
Professor Art Kramer, who led the study published in the journal Brain Research, said the findings had important _小题8:_ for encouraging individuals to take part in sport from a young age．"We knew that experience and environmental factors and socioeconomic status all _小题9:_ brain development," he said．"If you get some lousy（坏的） genes from your parents, you can't really fix that, and it's not easy to do something about your economic status．But here's something that we can do something about．