r u an idiot? :D

I saw this is on someone's siggy at deviantart...

This is this cat
This is is cat
This is how cat
This is to cat
This is keep cat
This is an cat
This is idiot cat
This is busy cat
This is for cat
This is forty cat
This is seconds cat
Now read the THIRD word only, in each sentence.

I'm an idiot -_-