What are Prepositions
Prepositions are those words, which show the relationship of Nouns (or Pronouns) with the other words in the sentence. Prepositions are used before Nouns (or Pronouns) in the sentence.
Across is used to show the movement from one side to another side or from one place to another place. Across is used to show the position of the nouns or the pronouns. It is also used to describe the whole or the most part of the object.
I walked across the road.
The government built a bridge across the river.
He was found dead across the border.
The scheme will be implemented across the country.