A missionary suddenly realized that the one thing he hadn't yet taught the natives he served was how to speak English, so he takes the chief for a walk in the jungle. He points to a tree and says to the chief, "This is a tree." The chief looks at the tree and grunts, "Tree."
The missionary is pleased with the response. They walk a little further and the missionary points to a rock and says, "This is a rock." Hearing this, the chief looks and grunts, "Rock."
The missionary is really getting enthusiastic about the results when he hears a rustling in the bushes. As he peeks over the top, he sees a couple of the natives in the midst of heavy sexual activity.
Flustered, the missionary quickly says to the chief, "Riding a bike."The chief looks at the preoccupied couple briefly, pulls out his blowgun and kills them.
The missionary goes ballistic and yells at the chief that he has spent years teaching the tribe how to be civilized and be kind to each other."How could you kill these people in cold blood that way?" he demands.
"My bike", the chief replied.