Dr. Seuss' lost tounge twister

see if you can do this:

This is this cat

This is is cat

This is how cat

This is to cat

This is keep cat

This is a cat

This is dumbass 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. Betcha you can't resist passing it on.