题目内容：
回答题：ExercisingYourMemory
1Agingdoesnotmeanadramaticdeclineinmemorypower,unlessyouhelpithelpbylettingyourmindgo.
2That'snottosaythatmemorydoesn'tchangethroughoutlife.Researchersdividememoryintocategoriesbasedonthelengthoftimewhenmemoriesarestored.Onesystemdividesitupasshort-term（lessthanoneminute;rememberingatelephonenumberwhileyoudial,forinstance）,long-term（overaperiodofyears）andverylong-termmemory（overalifetime）.
3Short-termmemoryisn'tmastereduntilaboutage7,butafterthatyouneverloseit.Long-termmemory,however,involvesmoreeffortandskillandchangesthroughlife.It'snotuntiltheearlyteensthatmostpeopledevelopamaturelong-termmemory.
4First,wemustgetinformationintoourheadsthroughlearning.Learningstrategiescangetrusty（生锈的，迟钝的）withoutconstantuse.Highschoolandcollegestudents,whoareforcedtorepeatedlyexercisetheirlong-termmemoryabilities（atleastlong-termenoughtogetthemthroughafinalexam）,usuallydowellonmemorytests.Thelongeryoustayinschool,themorechanceyougettopolishyourlearningskills.It'snowonderthatmorehighlyeducatedpeoplehavemoreeffectivememoryskillsthroughoutlife.
5Althougholderpeopleingenerallearnsomewhatmoreslowlythantheydidwhenyounger,adramaticdifferenceexistsbetweenthosewhostayintellectuallyactive--reading,discussing,takingclasses,thinking--andthosewhodonot.Givingthebrainadailyworkoutisjustasimportantasexercisingyourmuscles.Brainworkkeepsyour learning strategies in shape, and this helps your memory to function at full capacity.
6 The next part of a healthy long-term memory is retention（保持力，记忆力）, the ability to store what you have learned. Memory researchers still do not know whether memories are lost -- whether they still exist in the brain nut our mental searching cannot turn them up, or have disappeared entirely as our brain ages.
7 The third necessity for memory is recall, the ability to mind the memories we have stored. Again, while aging has widely different effects on the recall abilities of different people, research indicates that the older we get, the longer it takes to recall facts. But slower recall is still recall. In fact, aging does not seem to have any effect on forgetting at all, which takes place at the same rate in younger and older people.
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