preposition is a word used to link nouns, pronouns, or phrases to other words within a sentence. Prepositions are usually short words, and they are normally placed directly in front of nouns. In some cases, you’ll find prepositions in front of gerund verbs.
\(1\). to refer to two things which are clearly separated
\(2\). when naming individual items (\(2,3\), or more)                                                        
Our house is between the mountains and the sea.
Switzerland lies between France, Germany, Austria and Italy.                            
amongwhen the items are part of a groupI’m trying to decide among these shirts.
beforeearlier than a certain point of timeCan you call me back before 5 pm, please?
behindat the back of somebody/somethingThe teacher was standing behind me.
period of time
(within the period) 
Nobody spoke during the presentation.
\(1\). reason or purpose
\(2\). length of time (how long the 
    action lasts)
This gift is for you.
It rained during the night for two hours.
withtogetherHe was with his friend when he saw me.