How many times does boron bond two H? Well, since there's one boron and three H atoms, that means there are three different orbitals. So that means we must develop three hybrid orbitals. So that means we can no longer use SP hybridization, because SP hybridization produces only two hybrid orbitals. And we need three, as we see in this case here. So that means we're not combining S and P, but we're combining three orbitals.