edgeoftheregularandirregularformsofEnglishpasttense.Inparticular,itprovidesfurtherevidenceforandnewinsightintotheexistingmodelsandshedslightonfurtherdetailsoftherepresentationandprocessingofregularandirregularformsfromtheperspectiveofthesecondlanguage1.Tobespecific,theresearchquestionsinthisstudyareasfollows:●Researchquestion1Whetherfrequencyeffectispeculiartoirregularforms?●Researchquestion2Whethersimilarityeffectispeculiartoirregularforms?●Researchquestion3WhethertheamountofexposuretoasecondlanguagehasaneffectonL2ers’representationoftheregularandirregularforms?●Researchquestion4Howaredoubletsrepresentedinmentallexicon?Thesignificanceofthisresearchisasfollows.Firstly,theresearchonL2ers’mental1Inthispaper,secondlanguageandinterlanguage,firstlanguageandnativelanguageareusedinterchangeably.3