Answer:
What begins with an E but only has one letter?
You can catch me but cannot throw me. What am I?
My days are numbered. What am I?
The more you work, the more I'll eat.You keep me full, I'll keep you neat. What am I?
Until I am measured, I am not known. Yet, how you miss me when I have flown. What Am I?
No matter how little or how much you use me, you change me every month.