Q:

About using "only" with present perfect

I have seen this sentence in a status from one of my facebook friends.  It doesn't sound right to me. 

We have only left the city for the day. 

I think that it should be something like:

We have left the city for only a day (just for a day).  

Which one is correct and what is the usage of only with present perfect?  I consider sentences like 

We have only seen a few of the sights of this marvelous city. 

to be correct, but the above sentence just doesn't sound correct for me.  

A:

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.