最佳答案:

　　12345ABCCA678910DDCBC1112131415ACBBD

最佳答案:

　　1617181920ACDDB2122232425ABDAB

最佳答案:

　　2627282930BCACC3132333435DDDCB36、Taking regular walks helps older people pay attention better than if they didn't exercise.37、Mice are tested in previous research.

　　38、41 adults were tested.

　　39、Going for a walk every 2 or 3 days for just 10 to 45 minutes can be good news for grandparents.

　　40、Yes，it can.

最佳答案:

　　41、country

　　42、stayed

　　43、meeting

　　44、nobody

　　45、hungry

　　46、remembered

　　47、think

　　48、order

　　49、nothing

　　50、around

最佳答案:

　　One possible version：

　　My classmate，Maggie，hardly ever does housework.She does her homework three hours every day.Once a month she goes camping in the country.She hardly watches TV.But she uses the Internet once a week.Every day she does some reading.She often does sports.She exercises five times a week and goes to the movies once a month.