Question

He walked ___ the river bank (preposition)

Answer 1

he walked along the river bank

Answer 2

He walked along the bank.

Detailed answer

Along is the most appropriate word to be used here as a preposition is being asked.

• We all know that preposition is a word that precedes a noun or pronoun, it should also have a relation with another word in the sentence.
• The word along makes the sentence proper and it signifies that a person is walking near to the bank of a river.
• For example, other words like below, or over the bank is incorrect as it, not a preposition.