Breakdown of Wszedłszy do budynku, funkcjonariusz dostrzegł pożar.
do
to
budynek
building
wejść
to come in, to enter
funkcjonariusz
officer
Questions & Answers about Wszedłszy do budynku, funkcjonariusz dostrzegł pożar.
Why does wszedłszy end in -szy instead of the usual -wszy?
It is formed from the perfective verb wejść (to enter). To make this anterior participle (meaning "having done X"), we look at the 3rd person masculine past tense: wszedł. Because the stem ends in a consonant right before the ł, we drop the ł and add -szy instead of -wszy. Thus, wszedł becomes wszedłszy.
Would wszedłszy change its ending if the officer were female or if there were multiple officers?
No. Adverbial participles like wszedłszy are invariable—they never change to match gender, number, or case. Whether it is one officer, a female officer, or ten officers, the word remains exactly the same.
Could I form this same type of participle from the imperfective equivalent, wchodzić?
No, anterior participles (which express "having completed an action") can only be formed from perfective verbs. If you wanted to say "while entering" to describe an ongoing, simultaneous action, you would use the contemporary adverbial participle from the imperfective verb: wchodząc.
Why use dostrzegł here instead of a more common word like zobaczył?