搜索
Chapter11:MoreonVerbTensesYouhavealreadystudiedinChapterTenthefourmainverbforms.Theseverbformsarecombinedwithhelpingverbstocreatetensesotherthanthesimplepresentandsimplepasttenses.Sometensesdescribethecontinuationofactionfromthepasttothepresentorthepresentintothefuture.Inaddition,sometensesdescribemorethanoneactionbeingcompletedinthepast,butatdifferenttimes.Thesearetheprogressiveandperfecttenses.Theprogressivetenseiscreatedusingaformoftheverbbewiththepresentparticipleofthemainverb.Theperfecttensesarecreatedbycombiningaformofthehelpingverbhavewiththepastparticiple.Itisimportantnottoconfusethesetenseswiththesimplepresentandsimplepasttenses.Aneasywaytoseparatethemistorememberthatboththeprogressivetenseandtheperfecttensesusehelpingverbs.Simpletensesdonotuseahelpingverb.Itisimportantwhenyouworkwiththepastparticipletoputthe-dendingontheparticipleparticularlyfortheverbsuseandsuppose.Inaddition,makecertainthatyoudonotsubstitutetheprepositionoffortheverbhaveinphraseslikecouldhave,wouldhaveandshouldhave.