About 2, 3 and 4 letter roots I found interesting:
§30. Stems and Roots: Biliteral, Triliteral, and Quadriliteral.
I asked the question in FB and here are some responses: Kelly ... : I think we see this in English: We see her We view her We look AT her לצפות gets translated as "to watch" or "to view" but in Hebrew it takes on a preposition like the English "to look." Prepositions are tricky, different languages are different and it is what it is. Vedrana ... : I think צופים goes with preposition ב and than preposition get endings. watching him would be צופים בו