[selena]

Though this may actually be spelling, I dunno, it still confounds me.

The munchkin has a spelling list of plural possessive's this week.

One of the words on the list is class's.

That boggles my mind.

Why is it not class'?

I have toyed with the notion of emailing the teacher to find out. Then I decided I'd rather expose my ignorance to you all than to her.

And I can't find the answer on the Net. So edjumacate me, please.