There are many English words that you can add an “s” to make it plural. But far fewer words become singular when you add an “s”. What are two examples of these much rarer words?
The moon. The moon has a long association with being crazy (lunar being the basis for a lunatic). It shines at night, when you go to bed. The moon’s gravity creates the ocean tides and when the moon is different colors it can mean bad weather is on its way.
Any 5-letter word with the word ‘one’ somewhere in it. Examples include shone, stone, alone, money, loner, phone or ornery. Note it doesn’t say there is only one letter left, but only ‘one’ left. Tricky tricky.
You have a fox, a chicken and a sack of grain. You must cross a river with only one of them at a time. If you leave the fox with the chicken he will eat it; if you leave the chicken with the grain he will eat it. How can you get all three across safely?
Take the chicken over first. Go back and bring the grain next, but instead of leaving the chicken with the grain, come back with the chicken. Leave the chicken on the first side and take the fox with you. Leave it on the other side with the grain. Finally, go back over and get the chicken and bring it over.