How is the library located in relation to the bank?

The phrase "across" suggests a position that is separated by a street or an open space, signifying that the library is located on the opposite side in relation to the bank. This indicates a clear spatial relationship between the two buildings, where one can easily see the other from a distance, commonly found in urban settings. This is the most precise way to convey that the library and the bank are not adjacent but are in close enough proximity to be referred to as being "across" from each other.

In contrast, the terms "next to," "behind," and "above" imply different spatial relationships. "Next to" indicates direct adjacency, as if the two buildings are touching. "Behind" denotes that one building is positioned at the back of another, which implies some sort of obscured view. "Above" suggests vertical placement, indicating that one building is located on a different level or floor than the other, which doesn't fit the context if both structures are on the same horizontal level. Hence, "across" accurately captures the intended spatial relationship between the library and the bank.