Grapes are sour.

Once a hungry fox was searching for food in the forest. After a while he came to a vineyard. He was very tempted at the sight of graps. But the graphs were hanging very high. They were too high from the ground. It was beyond the reach of the fox. So the fox jumped again and again to catch the nearest bunch of graps but failed. At last he got tired and left the vineyard saying I will not eat these grapes because they are sour.