Question

We had to use a bridge to go ____ the river

Answer 1

We had to use a bridge to go across the river.

I think..

Answer 2

We have to use a bridge to across the river.

This is the right sentence and it includes pre-prepositions to be filled in the gap.

Filling the right prepositions are always taking place with correct answers filled in the complete sentences.

This is depending on the clause included in the sentence and able to deliver right sentence by prepositions words.