Sentence 1: Chuck and his pal Dave were going white water rafting. 
 Sentence 3: Chuck fell off the raft into the icy water 
 Sentence 4:  Fortunately he was wearing a life jacket 
 Sentence 5:  He floated along until the raft was able to reach him 
 Given Sentence 2: They didn't realize how fast and cold the water would be.