Onlywhenyouhaveobtainedsufficientdata________cometoasoundconclusion.
Night________(fall),wehurriedhome.
________(fail)severaltimes,theyneedsomeencouragement.
heteachertoldthemsincelight________(travel)fasterthansound,lightning________(appear)togobeforethunder.
Herefusedtotelluswhetherhe________(undertake)thejob.
Ipreferthisdiagram________thatone.