Complex sentence: Here boric acid acts as a Lewis acid and accepts an electron pair from the oxygen of one water molecule, which in turn donates a proton to a second water molecule and, therefore, acts as a Brønsted acid.
Split into simpler sentences: Here boric acid acts as a Lewis acid and accepts an electron pair from the oxygen of one water molecule. The water molecule in turn donates a proton to a second water molecule and, therefore, acts as a Brønsted acid.