In Gerunds^x, Whom^x, Genitives^x

Here are some examples The main point is to explain the correct answer The sentences are little-bit childisch ;they are some modified sentences. I am afraid that my explanations seems to be a little childisch, too. So please help me how to turn it into the right explanation. Mary was real...

Paco, I too was taught the "one's doing" formulation in the sixties and have never stopped using it, and neither have any of my friends and family whom I consider careful speakers of English. I have also found it to be universally followed in American formal writing (anything from newspapers to...