The old man married the young. A year later, her grandfather brought her to the hospital to give birth.

The old man married the young.
A year later, her grandfather brought her to the hospital to give birth. - Well, you give!
the doctor said. — You must always keep the engine running!
Grandpa answered proudly. A year later, he again brings his wife to give birth. - Well, grandpa, you can! the doctor was surprised.

— The motor must be kept working!
Grandpa answered proudly. A year later, the wife gives birth again. Doctor to grandfather: Doctor to grandfather: - Hey, grandpa, change the oil - a little black was born! ! !