Take your time and see if you can read each line aloud without a mistake. The average person can't.

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 go back and read the THIRD word in each line from the top down. I bet you can't resist passing it on when you're done!