"We see in front of us a small cat."
Translation:אנחנו רואים מולנו חתול קטן.
I realize this question is from 3 years ago but when I first learned this lesson I had the exact same question. It wasn't until later on that I discovered the answer. I am here doing strengthening exercises and I happened to see this question so here's a delayed response but one that was applicable to me a few months ago.
So there is a whole skill later on in Duolingo exactly about this. To summarize, when you don't include the personal pronoun and just use the verb רואים you are signaling a general type of statement that gets translated roughly as "one sees" or "they see." Of course, in the example we are working with this wouldn't work very well because of the preposition מולנו which means "in front of us" and that would give us trouble in a generic sentence. But had the sentence been: רואים חתול קטן you could translate that as "one sees a small cat." Or conversely with the personal pronoun, i.e. אנחנו רואים חתול קטן would be "we see a small cat."
I hope this comment helps the next person.