Here's my problem:
I've been confused about the placement of adverbs in present/past perfect phrases. For example, which sentence would sound better:
"We had been slowly drifting down the river when a bear attacked."
"We had slowly been drifting down the river when a bear attacked."
Personally, I'd go with the former, and this led me to believe that if the sentence contains both "had been" and a verb, the adverb should be placed after "had been"--if the adverb is indeed modifying the verb.
This, however, led to me to think of other uses of the present/past perfect, where another verb isn't present. The is the best example I could formulate:
"He has always been an academic and a charitable person."
See, right there, always--an adverb of frequency--was placed in between has and been.
Does this mean only adverbs of frequency (e.g., always, usually, etc.) should be placed in between such constructs?
A final example to put this topic over the edge is "He had been either sick or exhausted." Now, if you were to move "either" in between "had been," would the sentence be grammatically incorrect? I've noticed that the former is used more frequently, but the sandwiched version doesn't sound wrong either.