We live in a world full of lies and liars and we know little how to find out what it is a lie or a real fact. Actually, we live among lies and liars. We are liars ourselves and we can't stop telling lies.
English in a Minute: Little vs A little (BBC Learning English)
How to spot a liar (TED talk)
Some articles for you to read and a listening exercise about the issue:
The race to create a perfect lie detector... (The Guardian)
Listening exercise for you to do: Can you tell when someone is lying? (6 Minute English, BBC Learning English)