Solution:

The letter 'N'

Solution:

See o double you

Solution:

Its a paradox

=> A sentence that always contradicts itself and yet might be true.

Solution:

All numbers(0-9) appears in alphabetical order and once.

Solution:

Both come out at night

Solution:

I am a secret.

Solution:

Chicago

Solution:

Footsteps

Solution:

A green paint off-course :p

Solution:

I am a Clock