Sentence 1: Dan went spelunking into a cave with some friends. 
 Sentence 3: One of the caves produced a very funny and deep echo 
 Sentence 4:  The group sent a few minutes playing with this before leaving 
 Sentence 5:  Upon getting out of the cave, Dan told everyone he had a great time 
 Option 1: The cave started to creak and small pieces began to fall. 
 Option 2: The cave lead into a series of tunnels, and some were very large.