Sentence 1: Sandy and Ron had just bought a new house. 
 Sentence 3: The couple had a young son 
 Sentence 4:  They were concerned about their child's safety 
 Sentence 5:  Sandy and Ron enrolled their son in swimming lessons 
 Option 1: There were a lot of cactus in the backyard. 
 Option 2: There was a pool in the backyard.