She recommended me that I take a few days off from work.
She recommended THAT I TAKE a few days off from work. --> Common expressions followed by the subjunctive: recommend that | demand that | request that
I tried to explain him the problem, but he had difficulty understanding me.
I tried to explain the problem TO HIM, but he had difficulty understanding me. --> Also: recommend, describe
I don’t know why you didn’t go. If I were you, I should have gone.
I don’t know why you didn’t go. If I were you, I WOULD/ MIGHT/ COULD have gone. --> hypothetical past expressing regret = should