【关于虚拟语气的选择题,NOsistercouldhavebeensweeterthanyou.Ihavebeenlyingherethinkingif____whetheryouwouldtakemybaby.A.dieB.haddiedC.shoulddieD.woulddie.为什么选C呢?hedideverythingformethatmyfather___if_】

　　关于虚拟语气的选择题,

　　NOsistercouldhavebeensweeterthanyou.Ihavebeenlyingherethinkingif____whetheryouwouldtakemybaby.

　　A.dieB.haddiedC.shoulddieD.woulddie.为什么选C呢?

　　hedideverythingformethatmyfather___if___he

　　A.did...livedB.hadtodo...wouldhavelived

　　C.woulddo...livedD.couldhavedone...hadlived

　　为什么选D,C哪里不对?