A missionary is in Africa trying to teach the head of the tribe how to speak English.

As they walk through the jungle he points things out. "That's a tree" and his student says "tree!". They walk on a little further and see an animal. "That's a monkey." "Monkey!" They walk even further into the jungle and see two people on the ground having sex. Flustered, the missionary exclaims "Man riding bicycle!" The student doesn't say a word and raises his spear.
With one fell swoop he expertly throws it and the man on top falls dead to the ground. "What the hell did you do that for?!?" exclaims the missionary.
"Man riding MY bicycle!!"