a phrasal verb is an expression that consist of a lexical verb plus an adverb or preposition or both an adverb and a preposition

some phrasal verb are formed with adverb,i.e words such as away,by,back,down,of,on or out

after the storm passed,the wind gradually died down

some phrasal verd are formed with preposition,i.e words such as at,for,by,into,of,on and with

the horse suddenly broke into a gallop

some phrasal verb are formed with adverb and preposition

she says that if he won't marry her,she'll do away with herself