【关于dressup这个用法例1.LastChristmas,thecircusowner,JimmyGates,decidedtotakesomepresentstoachildren'shospital.DressedupasFatherChristmasandaccompaniedbya'guardofhonour'ofsixprettygirls,hesetoffdownthemainstree】

　　关于dressup这个用法

　　例1.LastChristmas,thecircusowner,JimmyGates,decidedtotakesomepresentstoachildren'shospital.DressedupasFatherChristmasandaccompaniedbya'guardofhonour'ofsixprettygirls,hesetoffdownthemainstreetofthecityridingababyelephantcalledJumbo.

　　2.ShewasdressedupinherSundaybest.

　　3.Afterhavingdecidedtotakesomepresentstoachildren'shospital,thecircusowner,JimmyGatesdressedupasFatherChristmasandsetoffdownthemainstreetofthecityridinganelephantcalledJumbo.

　　4.Hewasgoingtolendmeapoliceman'suniformsothatIcoulddressupfortheparty.

　　我想问的是dressup不是应该要用被动语态的吗?为什么例3,4直接用主动语态的呢?为什么例1,2就用被动?请问例34有错吗?例134都是出自于新概念英语2册第65课,两种用法都对吗?请讲解一下个中原因,

　　例3可否改成Afterhavingdecidedtotakesomepresentstoachildren'shospital,thecircusowner,JimmyGateswasdressedupasFatherChristmas.HesetoffdownthemainstreetofthecityridinganelephantcalledJumbo.

　　例4可否改成Hewasgoingtolendmeapoliceman'suniformsothatIcouldbedressedupfortheparty.