Pronounced as one letter,
And written with three,
Two letters there are,
And two only in me.
I am double, I am single,
I am black blue and grey,
I am read from both ends,
And the same either way.

What have one eye but still cannot see?

In four steps you need to move the word 'cold' From 'warm' by replacing one alphabet at a time such that every word formed at each step is acceptable in English Dictionary.

Which is the correct shadow of the bird?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

These types of puzzles are known as charades. What you have to do is find two words that are referred to in the first stanza and the second stanza and put them together to form the third word in the third stanza.

Just for example, if my first refers to 'off' and my second refers to 'ice', then my whole will be office.

My first is present - future's past -
A time in which your lot is cast.

My second is my first of space
Defining people's present place.

My whole describes a lack of site -
A place without length, breadth, or height.

Which point will the car reach to go out?

When I go in I might cause pain. I cause you to spit and ask you not to swallow. I can fill your hole. What am I?

The dirtier I get, the whiter I look. Who am I?

I’m orange, I wear a green hat and I sound like a parrot. What am I?