BE + PREPOSITIONS

BE ON1) Reflecting one of the meanings of the phrasal verb PUT ON, a frequent meaning of on by itself is “scheduled”. A typical use might be:
Example: There are six matches on in the evening.

2) Another common meaning – “operating” – is found with devices that we SWITCH ON, like lights and engines. Thus, saying “THEY ARE ON”means lights are shining, engines running.
BE OFF1) This can be an opposite of on, meaning either “POSTPONED” or “NOT OPERATING”. A related meaning is “UNAVAILABLE” to describe an item on a restaurant menu.

2) In addition, there is a meaning similar to that in the phrasal verb SET OFF, i.e. “starting” or “leaving”. It is common, for example, to hear racing commentators mark the start of a race with the words “THEY’RE OFF”. In the film The Wizard of Oz, a song marking the start of a journey to meet him begins with the words “WE’RE OFF TO SEE THE WIZARD”.

3) a third meaning is “NO LONGER EDIBLE”. Sour milk, for example, may be referred to as OFF.
BE IN1) Probably the most common usage is to say that somebody is “PRESENT WITHIN THEIR HOME/WORKPLACE”.

2) However, in certain restricted situations other meanings are found. In the games of cricket and baseball players ARE IN when it is their turn to try and amass points on the field.

3) in the context of a communal plan or decision, a person who IS IN has agreed to be involved in it (the phrasal verb join in).
BE OUT1) the main meaning of this word after be is probably “ABSENT ON AN ERRAND”. The absence will be brief and could be from home or the workplace. An alternative is NOT IN. Out can also be used in a variety of more restricted ways:

2) lights can be described as OUT instead of off when they are no longer providing illumination (turn out/off).

3) Workers on strike are sometimes said to be OUT (walk out).

4) in the games of cricket and baseball, a player IS OUT when s/he is forced to give up the points-scoring role on the field.

5) a person who has lost consciousness is sometimes said TO BE OUT.

6) a recently-released prisoner could also be labelled OUT.
BE UP1) usually, saying that somebody IS UP means they are no longer in bed (GET UP). In East Africa, there is an alternative meaning of “in a higher part of a building”, but Standard English prefers to say this with upstairs or, if the speaker is in a lower part of the same building, (up) above.

2) Buildings can also be described as UP, meaning that their construction has just been completed (PUT UP).

3) The expression TIME IS UP means that a deadline has been reached.

4) The question WHAT’S UP? means “What problem are you affected by?”
BE DOWN1) One use of DOWN means the opposite of up in the “constructed” sense, i.e. “DISMANTLED” (cp. PULL DOWN).

2) Related to this is a use with computer systems meaning “TEMPORARILY NOT OPERATING”.

3) BE DOWN could also describe SOMEONE WHO HAS RECENTLY MOVED FROM A HIGHER PART OF A BUILDING TO A LOWER ONE.

4) Recent descent is also suggested, in a more metaphorical way, when down describes either someone “VISITING THE SOUTH FROM THE NORTH” , or body temperature that is “LOWER THAN BEFORE”.

5) One other meaning of down after BE is “UNHAPPY”or“DEPRESSED”.
BE AWAY1) The basic meaning of this word (which is never actually a preposition) is similar to the “ABSENT ON AN ERRAND” However, it conveys a more extended absence: sleeping somewhere else for at least one night. A person on holiday, for example, might be described as away.

2) Less commonly, reflecting the meaning of GET AWAY, people can be labelled away AFTER ESCAPING THE EFFORTS OF OTHERS TO RESTRICT THEM, FOR EXAMPLE ON A SPORTS FIELD. !!! Escapees from prison, however, would not normally be described as away.
BE THROUGH1) A DRILL OR BORING MACHINE CAN BE DESCRIBED as THROUGH when it has reached the far side of what it is being used on (BREAK THROUGH).

2) A metaphorical extension of this meaning is “IN TELEPHONE CONTACT” (GET THROUGH).

3) A very informal usage, often applied to two people ending a romantic relationship, means “FINISHED”.
BE NEARThere does not seem to be much difference between this word and the more adverbial NEARBY. After «BE», «NEAR» is perhaps preferred with travellers rather than places, suggesting that the nearness is a result of movement.
BE OVERA very frequent meaning of this after BE is “FINISHED” (e.g. work is over). In addition, «OVER» can mean “HERE” or “VISITING”, but only with a suggestion that the visitor has crossed some kind of barrier, such as the sea. For example an American in Europe might be asked:

— How long ARE you OVER for?

However, if the barrier is flat and more local, «ACROSS» might be preferred.
BE UNDERTo describe someone as UNDER is often to say that they ARE UNCONSCIOUS AS A RESULT OF ANAESTHESIA.
BE UP AGAINSTCONFRONTED WITH; FACING
Example: He is up against a strong opponent.
BE UP TO1) OCCUPIED WITH, ESPECIALLY DEVISING OR SCHEMING
Example:What are you up to?

2) ABLE TO DO OR DEAL WITH
Example: I’m not up to a long drive.

3) DEPENDENT ON:
Example: The success of this project is up to us.

4) TO THE POINT OF; AS FAR AS OR UNTIL
Example: I’m up to chapter 15 in my book.
BE INTOBE INTERESTED IN OR INVOLVED WITH SOMETHING.
Example: She‘s really into yoga.