Firemanhadbeenfightingtheforestfornearlythreeweeksbeforetheycouldgetitundercontrol.引导的是时间状语从句.
Whenthefirehadatlastbeenputout,theforestauthoritiesorderedseveraltonsofaspecialtypeofgrass-seedwhichwouldgrowquickly.引导的也是时间状语从句.
Inplaceofthegreattreeswhichhadbeengrowingthereforcenturiespatchesofgreenhadbeguntoappearintheblackenedsoil.引导的是定语从句