That's how we learned it in Formal Logic (which I recommend taking if you get a chance; it's a huge help on LR and LG, and just getting your mind in that mode of thought for the whole test).I think the key here is that "does not exclude" =! "means"
"Some" does not exclude "all". However, it does not necessarily mean all.
True: All -> some
Not necessarily true: Some -> all. (though could be true)
And now I think my brain has imploded.
I still like the other definition given. (at least one.)
Yeah, I think that's the easiest way to define it.