use '?' for JOKER (blank)

From letters C, A, R, B, U, R, E, T, O, R, S  I made following words

11 letter words

carburetors[15]

10 letter words

carburetor[14]

9 letter words

carburets[13], turbocars[13], barretors[11], tabourers[11]

8 letter words

braceros[12], cabestro[12], cabresto[12], obscurer[12], carburet[12], turbocar[12], barretor[10], aborters[10], taborers[10], creators[10], reactors[10], carouser[10], tabourer[10], saboteur[10], outraces[10], curators[10], robuster[10], courters[10], arrestor[8]

7 letter words

bracero[11], boraces[11], bracers[11], rubaces[11], subrace[11], bescour[11], obscure[11], curbers[11], becrust[11], becurst[11], arbores[9], coarser[9], aborter[9], taborer[9], creator[9], reactor[9], boaster[9], boaters[9], borates[9], rebatos[9], sorbate[9], coaster[9], coaters[9], recoats[9], barrets[9], barters[9], carters[9], craters[9], tracers[9], carrots[9], trocars[9], rectors[9], acerous[9], carouse[9], bursera[9], curares[9], arbours[9], courser[9], scourer[9], burrers[9], outrace[9], curator[9], courter[9], acetous[9], arbutes[9], bursate[9], curates[9], abortus[9], robusta[9], rubatos[9], tabours[9], cuatros[9], surcoat[9], turacos[9], obtuser[9], couters[9], croutes[9], scouter[9], burster[9], roarers[7], roaster[7], terrors[7], arouser[7], rouster[7], routers[7], tourers[7], trouser[7]

6 letter words

bracer[10], braces[10], cabers[10], carbos[10], carobs[10], cobras[10], bracts[10], rubace[10], curber[10], cubers[10], boreas[8], coarse[8], barres[8], rebars[8], carers[8], racers[8], scarer[8], arbors[8], borers[8], resorb[8], corers[8], crores[8], scorer[8], boater[8], borate[8], rebato[8], coater[8], recoat[8], barret[8], barter[8], carter[8], crater[8], tracer[8], carrot[8], trocar[8], rector[8], costae[8], barest[8], baster[8], breast[8], tabers[8], carets[8], cartes[8], caster[8], caters[8], crates[8], reacts[8], recast[8], traces[8], aborts[8], boarts[8], tabors[8], actors[8], castor[8], costar[8], scrota[8], tarocs[8], sorbet[8], strobe[8], corset[8], coster[8], escort[8], rectos[8], scoter[8], sector[8], curare[8], arbour[8], burrer[8], abuser[8], bursae[8], causer[8], cesura[8], saucer[8], soucar[8], bourse[8], cerous[8], course[8], crouse[8], source[8], bursar[8], curers[8], curser[8], recurs[8], burros[8], roarer[6], soarer[6], errors[6], terror[6], oaters[6], orates[6], osetra[6], arrest[6], rarest[6], raster[6], raters[6], starer[6], tarres[6], terras[6], rostra[6], sartor[6], resort[6], retros[6], roster[6], sorter[6], storer[6], arouse[6], rasure[6], urares[6]