Answer:
I begin your sentences.
I know a word of letters three. Add two and fewer there will be. What is the word?
Light hides me and darkness kills me. What am I?
When young I am sweet in the sun. When middle-aged I make you gay. When old I am valued more than ever.
My rings are not worth much, but they do tell my age. What am I?
I met a man on the London bridge, he tipped his hat and drew his name, in this riddle I told you his name. What is it?