Answer:
I'm written with two letters, said with one and seen with two. What am I?
You cannot keep me until you have given me. What am I?
I like to twirl my body but keep my head up high. After I go in, everything becomes tight. What am I?
Sometimes dark and sometimes bright I make my way among twinkling lights. Seas and oceans obey my call yet mountains I cannot move at all. My face is marred and gray But I'm majestic anyway
My first is second in line; I send shivers up your spine; not quite shining bright I glitter in the light.
No matter how little or how much you use me, you change me every month.