改错题，下面这几道题都哪错了，为什么要这样改

1、Supposeyoualreadyknowtheendingofanovel,wouldyoustillhavetheinteresttoreadit?Theanswertothequestionmakesthedifference.

2、Oursanctionagainstyoursonisbynomeansirreversible.Behavehimselfandhewillbeallowedtocomebacktotheclassroom.

3、"Bedocareful!"themotherpleaded,"ifyoumakethismistakeagain,youwillhavenomorechancetogetajob."

4、Thecolonelexplainedhisplanwithconfidence:"Shouldtheenemyattackusfromtheoppositedirection,Iwilllaunchmycounterattackfromthemiddle,thuscuttingthemintwo."

以上这几题都哪里错了，为什么要这样改。