What word begins and ends with an E, but has only one letter?

I have a head like a cat and feet like a cat, but I am not a cat. What am I?

I go up and I go down.
I go up towards the beautiful sky and down toward the green ground.
I am present tense.
I am past tense too
Children love me.

Who Am I?

If eleven plus two equals one, what does nine plus five equal?

I possess a head

I flaunt a tail

But I don't have mouth or legs

Can you find out who I am?

I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?

Fate has decided that you will only be pleased to meet me when you need me

Maybe that is why, when I am working, I start working

However annoying I may be to the regulars, the little ones are always inspired

I will always be waiting if you try to reach me

How many of you can guess my name, let me see

I came first on earth but second on the heaven.
I also came twice in a week but found just once in a year.
I stay away from months but you can find me in February.

What am I?

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

What has many keys but can’t open a single lock?