Johnny races into the farmhouse and yells excitedly to his Grandpa, "Hey Grandpa, the bull is fucking the cow!"
Grandpa informs Johnny that he won't tolerate this sort of playground language on his farm and that in future if Johnny wants to inform him about such things, he should say something like "The bull is surprising the cow."
A few weeks later, Johnny is again visiting the farm. Once again he comes racing in and yells, "Grandpa, the bull is surprising the cows."
Grandpa says to Johnny, "I'm pleased to hear that after my conversation with you a few weeks ago, you have cleaned up your language"
"However, your grammar is not quite correct. It is not "the bull is surprising the cows"; it is "the bull is surprising the cow..."
The bull can only surprise one cow at a time."
Johnny replies, "No Grandpa, the bull is surprising all the cows because he's fucking the horse!"