Fill in the blank with appropriate prepositions.
When you have completed reading the book, keep it _______ the shelf.
Show answer & explanation
Correct answer: B
Explanation
On: This preposition is used to indicate that an object is resting on a flat surface. Since a shelf is a flat horizontal surface, you place a book "on" it.
In: This usually suggests the object is inside an enclosed space (like a drawer or a box). While sometimes used loosely, "on" is the standard choice for shelves.
Against: This implies that the book is leaning up against the back or side of the shelf, rather than just being placed there.
Across: This suggests movement from one side to another or placement that spans the width of the shelf, which doesn't fit the context of simply putting a book away.
Correct Sentence:
"When you have completed reading the book, keep it on the shelf."