Translation:Small mouse, small cow. Small dogs, small cats.
Arriving at this sentence for the first time, it is very frustrating: while it is good training for grammatical correspondence, its parts are too long and too similar for a first timer. Perhaps Duolingo should introduce a new type of exercise: a multiple one that consists of separate parts (four for this one) and you have to answer all of them properly to pass, but each of them is minimal (and you don't have to listen to the whole damn thing again and again... and again and again and again and again and again and again and again, forgetting the nuances of the beginning as you wait for it to end). As it is, it forces me to cheat my way through it and is therefore worthless. :(