Actually, if the cow eats, it should be "Die Kuh frisst langsam". "Essen" is only for people, not for animals. For animals, it is "fressen" (as I have learned from many people here at Duolingo). Should be much easier to distinguish. With people, of course, this is still a problem...
Sam, a businessman, was driving home after a long sales trip, and spotted a hitchhiker with a cow. Sam stopped, and the hitchhiker approached the window and said, "Will you give me a ride to Denver, sir?"
Sam was amazed and said, "I do not mind, but you will have to leave your cow here."
"No, sir," the hitchhiker said. "I will just tie her to the back of the car, and I promise you, sir, she will not slow you down. I promise."
The businessman was reluctant, but he was dying for company, so he agreed. The hitchhiker was elated, and tied the cow to the back bumper.
They started out, and Sam took the car up to 10 miles per hour. He looked in the mirror and the cow seemed to be trotting along. 20 mph, 30 mph, 40 mph did not phase the cow. The hitchhiker looked over to Sam and assured him that the cow would be fine, not to worry.
Sam took the car up to 55 mph, and still the cow was looking very comfortable. Now Sam was getting a little frustrated by this cow who could keep up with his car. Sam watched the speedometer go to 65, 75, and finally, 90 mph. Sam looked back, and FINALLY the cow seemed tired. "Hah! At last, I am getting to you!", he exclaimed.
"What is the matter?", the hitchhiker asked.
"Your cow seems tired; her tongue is sticking out," the businessman said.
"Is it sticking out on the left, or the right?", the hitchhiker asked.
"The left side," Sam said with a smile.
"Well," the hitchhiker said, "You better pull over—she is trying to pass you."