I have a question about the grammatically correct way to write something like this:?

I'm giving my mother a lesson on the basic rules of grammar so that she doesn't have to call me at all hours of the day asking me to proofread her letters and emails via telephone.

We are working on commas right now. Here is an example I gave her:

"I hope that my daughter doesn't think that I'm illiterate, simply because I cannot form a grammatically correct sentence."

I got a little confused myself with that one! Does it need the comma, or does it not? I know that if the "simply" wasn't in there it wouldn't, but does the "simply" change anything?

What is the general rule for this? I'm in college, so I write paper after paper without ever thinking twice about my grammar, and I never have any corrections about my grammar. However, now that I'm really thinking about this, I realize that I don't even know the rule on this!

Thank you very much! I'll pick a best answer TODAY!

hahahah

Mrs. Darryl, you are a smartass, aren't you? The funny thing is, however, that I realized that after I already submitted the question. Yahoo Answers, being the wonderful resource that it is, won't allow me to edit my question.

Three rules are in effect here:

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1) When the extra element follows the independent clause, you should separate them with a comma only if the element does not support the meaning of the independent clause. In such a case, the final element only adds extra information.
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You can test the rule by omitting the extra element and seeing if the sentence still conveys the same meaning albeit with less detail.

"I hope my daughter doesn't think I'm illiterate."

Part of the confusion with this example is that on the surface it seems to convey the same meaning (which would imply a comma is unnecessary) but I think you might argue that the meaning of the original sentence is actually:

"The inability to form a grammatically correct sentence is not enough reason to think I am illiterate."

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2) If the following dependent clause expresses strong contrast, separate it with a comma, even though it is essential.
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The word "simply" inserts a mildly sarcastic nature to the sentence, making the extra element antagonistic to the independent clause rather than supportive, thereby requiring the comma.

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3) You should always use a comma within any type of clause, if there is risk for ambiguity or confusion without using a comma.
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If you remove or move the comma to the other side of "simply" it's possible that the fear is that the daughter thinks she's illiterate simply, as opposed to illiterate with more complexity.

Yes the comma is needed. if you read the sentence out naturally, you will take a tiny break before simply..
This means there is a comma needed!

That one could go either way in my book. If I were writing that sentence I would not use a comma, but I wouldn't argue with someone else if they thought a comma to be necessary.

The general rule is this:
If you pause at that point while speaking the sentence, then the comma should be used. If you don't pause, don't use the comma.

The comma is necessary. If you don't have it at all you don't know if you are "simply illiterate," or if simply leads the next phrase.

With today's American current writing styles and writing dialects you may be able to get away with leaving the comma out, but I personally think it is more clear with it in there.

I would also hyphenate "grammatically-correct," as it is being used as an adjective.
Later...I honestly wasn't trying to be a smartass; I just think the phrase "grammatically correct" (used as two words describing a third) needs a hyphen.

Pay no mind to Mrs. Darryl.

"Grammatically" is an adVERB and should not be hyphenated with "correct."