At the moment I'm studying for a diploma in editing and book publishing. (If any of you have noticed I don't tend to post on Fridays, that would be because it's course day, and the course is in Sydney.) Yesterday's course notes included an article, Rules for Using the Possessive with Verbal Forms by Mary Stoughton.
Although these books all agree the possessive should be used with a gerund but not with a participle, a gerund and a participle both use the -ing form and therefore look the same, despite the fact that they function differently.
Now, I've studied more grammar than most english-speakers of my acquaintance, and still my head always starts to vibrate slowly when the concept of verb forms comes up. Even when it's stuff I know. But using the possessive in front of a verbal form? Maybe I know it, sub-consciously. When I read on, I found Stoughton slightly clearer:
Ultimately, then, it all comes down to a question of meaning: What's objectionable, the woman herself or the fact that she happens to be wearing pearls? If it's the former, no possessive is required. [I object to the woman wearing pearls.] If it's the latter, it takes the possessive to make the meaning clear. [I object to the woman's wearing pearls.] If the emphasis is on the noun, no possessive is used. If the emphasis is on the phrase or the thought, the possessive is used.
Okay, I thought. I think I understand what she's driving at. I can do this.
Nope. After the article was a test: ten example sentences, and I had to decide whether it was correct as written, or whether the possessive was required. I managed to be convinced they were all correct as written (and the simple fact I thought all of them were correct did lead me to think something was awry, yes).
The real number that were correct as written? One.
And I thought I knew some of this grammar stuff.