I am having a real brain fart here, and I would appreciate some help.
Now, I read this here - http://grammartips.homestead.com/adverbs2.html - but for some reason, in several cases my head just can't make the connection between the provided example for an adverb just modifying the verb and not the whole clause.
The example given:
Often the introductory adverb modifies just the verb, as does the word "often" in this sentence.
The cases my brain refuses to compute:
A) Usually it's the age that's a problem.
B) Finally he's had enough and stops me.
C) Eventually my eyes settle on a bottle of whiskey.
My purpose here is to know whether there should be commas after these words or not. And why. My problem is that I could, possibly, see each of these as just modifying the verb: A) it's B) had C) settle
And maybe I am stupid. Right now I feel stupid. Or is it: Right now, I feel stupid? I just don't know, anymore. Commas are really killing me. So if anyone could help me out here, in layman's terms, I would really appreciate it.