"can be clearly seen" OR "can clearly be seen" [duplicate]
Solution 1:
"Clearly" is ambiguous between interpretations as a manner adverb ("in a clear manner") or as a sentence adverb ("it is clearly the case that ..."). In your first example ("The results can be clearly seen"), in my opinion, the preferred interpretation is as a manner adverb, but the interpretation as a sentence adverb is also possible.
For the second example ("The results can be seen clearly"), with primary stress on "clearly", the interpretation is that of a manner adverb. However, with primary stress on "seen", it's a sentence adverb.
In sentence initial position ("Clearly, the results can be seen"), it's a sentence adverb, and also when the adverb comes after the subject ("The results clearly can be seen"). It's also a sentence adverb when it comes after the modal "can".