The Seashell<br>Daniel liked to dig at the beach. He always found interesting shells. Last time, he found a giant shell that had pink swirls. He took hit home on put it on a shelf. People always commented hon how beautiful it was.
Daniel keeps his shell collection on a shelf
The context only states that he put the nice looking shell on a shelf. It doesn't say if he collects shells, and if he does, where he keeps them. The system guessed that because the put the shell in question on a shelf he must put all his shells there.  
( z1 keep :ARG0 ( z2 person :name ( z3 name :op "Daniel" ) ) :ARG1 ( z4 collect :ARG0 z2 :ARG1 ( z5 shell ) ) :location ( z6 shelf ) )