Learn English – The placement of “only” in a sentence with perfect continuous tense and “been”

Knowing happens but once -- unlike waiting, you don't stretch the process of knowing someone over an extended period. It happens at a moment of time. That is why, I suppose.

You could, on the other hand, be getting to know the person better over ten years.

Careful (not to say pedantic) speakers place 'only' directly in front of the word or phrase it qualifies. So they would say: "I drink only water." The claim is that saying: "I only drink water" could be interpreted as meaning: "Drinking is the only thing I do with water, not washing in it or playing with it, etc."

In theory there may indeed be cases where the placement of 'only' is a source of ambiguity. In practice, however, it is unlikely that anyone would be confused, particularly in spoken language where intonation contributes to meaning.

"We have only seen a few of the sights of this marvelous city" sounds perfectly natural to me, a native speaker. In fact Google returns 3 times as many hits for "I have only seen ..." as for "I have seen only ... ".

As an aside, the sentences are in the present, not past, perfect. But the tense of the statement is irrelevant to considerations of where 'only' should be placed.