how long has the factory been open为什么open不用过去分词?

how long has the factory been open为什么open不用过去分词? How long has the shop been open How long has the shop__.A,been open.B been opened 答案是B为什么 How long has that factory been ____ It's been open ____ seve How long has this factory been open这句话转变成这样可以吗 this factory has been open for twenty years.为什么是open 而不是open the factory has been open for twenty years 还是the factory has open的过去分词 .The factory has been ________ for three years.A.to open B.o The factory has been ________ for three years.A.to open B.op The factory has been ------------- for two years.A.open B.to How long has this shop(）?Abe openB been open C opened Dbeen