Sentence 1: The man was walking to work. 
 Sentence 3: The river was very flooded and there was water on the bridge 
 Sentence 4:  He carefully hurried across it 
 Sentence 5:  He hoped the river would be down by the time he got off work! 
 Option 1: He had to cross the bridge over the river. 
 Option 2: He had to cross the bridge over the highway.