關於英文句法的問題?

unnoticed 未受到注意的 ~ adjective (we consider it as a pure adjective but not a past participle)

Original sentence in full:
(1) Two ground moles tired to slip by quietly.
(2) Two ground moles were unnoticed.
~ or, Two ground moles went unnoticed. (went is a linking verb too)

There are two ways to combine the sentences into one:

(A) participle phrase
~ Being unnoticed, two ground moles tried to slip by quietly.
~ Two ground moles tried to slip by quietly, being unnoticed.
~ Two ground moles tired to slip by quietly, unnoticed. (if you consider "unnoticed" as past participle)

(B) secondary predicate
~ Two ground moles tired to slip by quietly unnoticed. (comma is optional)

"unnoticed" is a predicative adjective as a (secondary) complement of the subject "two ground moles".
first & main predicate: tried to slip by quietly
second predicate: were unnoticed

Another example of secondary predicate:
He returned from the contest empty-handed.
** we can add an adverb to modify the verb of first predicate **
He hastily returned from the contest empty-handed.
He returned from the contest hastily empty-handed. (adverb of manner can be placed in front of the verb or at the end of the sentence)

unnoticed=adj.,not observed, not noticed
eg:-The moles slip by unnoticed.(=adj)
eg:-tired ---verb
eg:-to slip by quitely +unnoticed=adverb.phrase +adj.
The sentence:-eg:-Two ground moles tired to slip by unnoticed (=adj, qualifying the moles.(subject)