关于grow的.All of the flowers now ----- here have developed fro

关于grow的.All of the flowers now _____ here have developed from those _____ in the forestAll of the flowers now _____ here have developed from those _____ in the forest.A raised;once grewB raised;once growingwhy?麻烦帮我说说为什么用growing啊?如果有once grown对吗?