back means backwards to a place, a person etc. (= go back, come back, take something back etc.) (e.g. Can you please call me back?)

back away means to move in a direction opposite where one is facing, keeping some (or most) of your attention on the thing in front being avoided.

back off means retreat, to stop being involve in a situation, or to move backwards to get away from (e.g. The police told the protesters, then the crowd backed off.)

back up means to stop or to wait in a long line because there are too many of them (e.g. My car backed up for miles after the accident.) back up someone/ something means to provide support or help to someone or something (e.g. My boss always backs up my arguments with facts.) back something up means reverse, or to prove that something is true, or to make an extra copy of information (e.g. You should always have to have backup plans for any situation.)

be after means try to find, or get (e.g. A police car is after a sport car because of the high speed.)
be along means arrive (e.g. He said he'd be along after meeting is finished.)
be away means be elsewhere, on holiday, etc. (e.g. Mr. President is away on business for a week.)
be off means to a place (e.g. Ann is off to Korea. She’s off on annual holiday.)

beat up means in a bad condition (e.g. It’s a beat up old house.)
beat up someone/ beat someone up means to hit someone hard and repeatedly (e.g. A friend of mine was beaten up and stole his wallet. The government supporters are beating up by gangs who were arrested.)
beat up on someone means to attack someone unfairly (e.g. Young friends are always beating up on each other.)
beat yourself up means to blame or criticize yourself or someone else, usually unfair or unnecessary situation (e.g. It’s time to stop beating yourself up about it, just try it again.) 

blow out means extinguish (e.g. I will blow out a candle if we don't need it.)
blow over means gradually less important until it is forgotten (e.g. I thought that after a few days the argument would blow over.)
blow up means explode or suddenly very angry (e.g. Man accused of threatening to blow up the city hall. My parent blew up just after they heard my record.)
blow something up means to add air (e.g.We must blow tires up before we leave for Scotland.)

break down means 1) get upset or to be unable to control emotions (e.g. The woman broke down when we gave her the bad news.) 2) stop relationships (e.g. Ann’s marriage broke down after only a few weeks.) 3) stop working (for machines, cars etc.) (e.g. Sorry for late come because my car was broken down.)
break something down means divide into smaller parts (e.g. We should break the project down into a couple of areas.)

break in means 1) to enter house or building by force in order to steal something (e.g. Someone had broken in through the gate and stole our car.) 2) interrupt (e.g. The boss broke in to report of the annual sales performance.)
break something in means to familiarize someone something with a new (e.g. I bought these shoes yesterday. They should be OK after I break them in.)

break into something means enter with extra force or start doing something (e.g. The police broke into the building when they saw smoke.)

break out means begin or start, normally, dangerous or unpleasant event (e.g. The Korean War broke out in 1960.)
break out in something means develop a skin irritation condition (e.g. She broke out in a rash after the long business trip.)
break out of means escape (e.g. The prisoners broke out of jail last night.)

break up means start laughing or stop classes and start the holidays (e.g. The kids just broke up as soon as they saw a comedian. The School broke up for the summer holidays in Jun.)
break up of means divide into smaller groups (e.g. It will make our power weaker if we break up of team work.)
break up with somebody means separate (= split up) (e.g. I'm surprised to hear that Tom have broken up with Marry.)

bring something down means make unhappy (e.g. This sad news will bring people down.)
bring up means introduce something in a conversation, or raise, look after a child (e.g. They were brought up by my grandparents. Please don't bring it up again.)
bring someone up means teach to have beliefs (e.g. My parent brings me up to believe in our own abilities.)
bring something up means to start talking or to vomit (e.g. She was drinking so much I thought she'd bring up her dinner soon.)