He swam _____________ the river.
He swam _____________ the river.
Explanation
Usage of Across
Across has 3 different meanings.
1.From one side to other side. Like He swam across the river.
2.On the opposite/other side. Like we saw some old friends across the road.
3.When something stretches/extends from one side to another. Like there was a bridge across the river.