I have a sentence that begins with the word "today" and a sentence that begins with "frankly." My style guide says to add commas after introductory adverbs when they modify the entire clause after it, but I'm having trouble deciding when it does. Let me use "today" in a sentence.
"Today she didn't have time to visit her grandfather."
In that sentence, I am told that "today" doesn't modify the entire clause; I think otherwise. Isn't "today" technically modifying the entire clause? I'm not sure, and that's what I need help with. What are some clues to help determine if an introductory word modifying the entire clause after it?