This is my first post, so please excuse any mistakes in it.

I understand that a comma precedes a coordinating conjunction between independent clauses, but I have often seen sentences written like this:

Joey loved Dawson, but did not know how to tell him.

This example comes from an ACT study guide, so it is most likely structured correctly; but I don't understand how "did not know how to tell him" is an independent clause because it does not have the subject "Joey" or "he." Can someone please explain this to me?

Joey loved Dawson, but did not know how to tell him.

In my opinion, this is wrong, for the reason you already cited.


Let me offer a personal opinion.

I suggest you might find it enlightening if you take a moment to think about this in another way.

A comma represents a place where you would pause if you were saying the sentence to someone. So, can you think of any reasons that you might wish to pause in such a sentence?

All these rules about commas really just seek to codify the reasons why it seems reasonable to pause sometimes.

My feeling is that the rule as you quote it is a simplification, which really needs a lot more qualification.

In your example, I would probably pause to give the listener a moment to absorb what I have just said, before I went on to surprise him by the last part of the sentence.