We had to use the bridge to go _______ the river.
What should be the preposition: over or across?
People are divided in their opinion. Some say over, while others say across. Some even say that it could be both. What is the correct answer?
The answer is it could be both. Unprompted, a native English-speaking reader would instantly comprehend the meaning, most likely without a hitch.
Personally, I wouldn't use either, but would simply use cross
"We had to use a bridge to cross the river"
if the action concerned personal mobility, or span
"We had to use a bridge to span the river"
if the action concerned the placement of a permanent crossing.
Note that bridge can be used as a verb as well, but mainly in a figurative sense these days:
We were mostly successful in bridging the divide between good sense and good morals.
When it comes to getting from one bank of a river to the other the words "across" and "over" can be used interchangeably. An example of this interchangeability is one verse of the traditional song "The Waters of Tyne" from North East England. This verse is:
Oh where is the boatman, my bonny hinney
Oh where is the boatman, go bring him to me
For to ferry me over the Tyne to my honey
Or scull him across that rough river to me.
This refers to crossing a river by boat in the absence of a bridge but both words are used in spite of the fact that the boat travels through the water rather than over it. Both words can be used almost regardless of the actual method of crossing.