【1.Alltheinvestigations____beforethedeadline,thestaffdecidedtohaveapartyasacelebration.A.hadbeenfulfilledB.havingbeenfulfilled过去式的过去不是过去完成时吗?为什么选having...2.all____atthepresenttimeisanurgent】

　　1.Alltheinvestigations____beforethedeadline,thestaffdecidedtohaveapartyasacelebration.

　　A.hadbeenfulfilledB.havingbeenfulfilled

　　过去式的过去不是过去完成时吗?为什么选having...

　　2.all____atthepresenttimeisanurgentandrationaldecisionotherthanendlessdispute.

　　A.thatisneededB.thethingneeded

　　选B不行吗?为什么

　　3.Thehousewiveswouldusually____thefruitbeforemakingtheirmindsuowhichtobuy.

　　A.pickoutB.pickover

　　选B...两个都有挑选的意思,为什么选B来?

　　4.Withthefastdevelopmentandexpansionofcities,the___suburbsofwhichbecomeprosperous,too.

　　A.exteriorB.externalC.outerD.outside

　　选C..真是搞不清楚这四个“外部”的用法区别...求详解